Centre for Electronics Design & Technology of IndiaA Scientific Society under Department of Electronics,

Govt. of India, New Delhi

Published by CFS Documentation CellCentre for Electronics Design and Technology of IndiaAn Autonomous Scientific Society under Department of Electronics,Govt. of India,New Delhi.

First Edition: 1999

TRADEMARKS: All brand name and product names mentioned in this book are trademarks or registered trademark of theirrespective companies.

Every effort has been made to supply complete and accurate information. However, CEDTI assumes no responsibility for itsuse, nor for any infringement of the intellectual property rights of third parties which would result from such use.

No part of this publication may be stored in a retrieval system, transmitted or reproduced in any forms or by any means,electronic, photocopy, photograph, magnetic or otherwise, without written permission of CEDTI.

CEDTI/CFS/99/6/2.2/R1

FOREWORD

The information technology and telecom sectors have suddenly opened up avenues,which require a very large specially trained manpower. These sectors are highly dynamic andneed training and re-training of manpower at a rapid rate. The growing gap of requirement ofthe industry and its fulfillment has created a challenging situation before manpower traininginstitutes of the country. To meet this challenge most effectively, Centre for Electronics Designand Technology of India (CEDTI) has launched its nation-wide franchising scheme.

Centre for Electronics Design and Technology of India (CEDTI) is an AutonomousScientific Society under the Govt. of India, Department of Electronics with its Headquarters atNew Delhi. It operates seven centres located at Aurangabad, Calicut, Gorakhpur, Imphal,Mohali, Jammu and Tezpur. The scheme will be implemented and coordinated by these centres.

The scheme endeavours to promote high quality computer and information technologyeducation in the country at an affordable cost while ensuring uniform standards in order tobuild a national resource of trained manpower. Low course fees will make this educationavailable to people in relatively small, semi urban and rural areas. State-of-the-art training willbe provided keeping in view the existing and emerging needs of the industrial and Govt.sectors. The examinations will be conducted by CEDTI and certificates will also be awardedby CEDTI. The scheme will be operated through all the seven centres of CEDTI.

The CEDTI functions under the overall control and guidance of the Governing Councilwith Secretary, Department of Electronics as its Chairman. The members of the council aredrawn from scientific, government and industrial sectors. The Centres have separate executivecommittees headed by Director General, CEDTI. The members of these committees are fromacademic/professional institutes, state governments, industry and department of electronics.

CEDTI is a quality conscious organisation and has taken steps to formally get recognitionof the quality and standards in various activities. CEDTI, Mohali was granted the prestigiousISO 9002 certificate in 1997. The other centres have taken steps to obtain the certification asearly as possible. This quality consciousness will assist CEDTI in globalizing some of itsactivities. In keeping with its philosophy of ‘Quality in every Activity’, CEDTI will endeavour toimpart state of the art – computer and IT training through its franchising scheme.

The thrust of the Software Courses is to train the students at various levels to carry outthe Management Information System functions of a medium sized establishment, manufactureSoftware for domestic and export use, make multimedia presentations for management andeffectively produce various manufacturing and architectural designs.

The thrust of the Hardware Courses at Technician and Telecommunication EquipmentMaintenance Course levels is to train the students to diagnose the faults and carry out repairsat card level in computers, instruments, EPABX, Fax etc. and other office equipment. AtEngineer and Network Engineer levels the thrust is to train them as System Engineers toinstall and supervise the Window NT, Netware and Unix Networking Systems and repairMicrocontrollers / Microprocessor based electronic applications.

An Advisory Committee comprising eminent and expert personalities from the InformationTechnology field have been constituted to advise CEDTI on introduction of new courses andrevising the syllabus of existing courses to meet the changing IT needs of the trade, industryand service sectors. The ultimate objective is to provide industry-specific quality education inmodular form to supplement the formal education.

The study material has been prepared by the CEDTI, document centre. It is based onthe vast and rich instructional experience of all the CEDTI centres. Any suggestions on theimprovement of the study material will be most welcome.

(R. S. Khandpur)Director General (CEDTI)

TABLE OF CONTENTS

UNIT CHAPTER NAME PAGE NO.

SECTION - A

1 An Introduction to Database 11Management System

2 Database Creation, Its Handling 15And Report Generation

3 Command File Loops And 37Decision Making in Structure Programming

SECTION - B

4 Screen Generation And Object Adding 61

5 Relational Query By Example 69

6 Object Linking And Embedding 73

7 Making Applications Project And EXE Files 81

PREFACE

Databases play an important role in business engineering, medicine, law, education and library

science. Database constitute the most important component of any computer based information

systems. In view of this, it has become increasingly important for any working professional to

acquire the programming skills for developing database application software.

This course material introduces the advance concepts for designing, using and implementing

database systems using FoxPro 2.6. This book stresses the advanced features of database

modelling and designing, the languages and facilities provided by database management

systems and system implementation technique. This text is designed to provide the knowledge

of the role of database systems in business operations, management decision making, and

the strategic success of organisations. The goal is to help students become managerial end-

users who can propose and participate in developing database solutions to business problems.

The objective of the course is to train students to be expert users of database management

systems as well as a skilled programmer of a database management application software.This

course material is divided into two sections. Section A introduces the students to the basic

principles of Database Management Systems and the salient features of the FoxPro

Programming. This Section also instructs the students to create and maintain database using

FoxPro, implement the various types of loops and decision making statements. Section B

gives an introduction to the various enhanced features of FoxPro which includes Screen

creation and adding objects to screen, Relational Query by Example, Object Linking and

Embedding and development of application projects and creation of executable files.

Assimilation exercises have been given at the end of each chapter to facilitate the students to

carry out the self check of the level of understanding achieved during the course of the study.

SECTION - A

COMPETENCY OBJECTIVES

The objective of this Section is to introduce the students to the basic principles ofDatabase Management Systems and the salient features of the FoxPro. At the end of thesection, a student should be able to :-

v Create and maintain database using FoxPro.v Understand & implement the various types of loops.v Highlight the importance decision making statement.v Implement the procedures in FoxPro.

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CHAPTER - 1

AN INTRODUCTION TO DATA BASEMANAGEMENT SYSTEM

DATA BASE :

A database is a collection of related data. By data, we mean known facts that can be recordedand that have implicit meaning. Therefore, a collection of related data with an implicit meaningis called database. A database can be of any size and of varying complexity. It may be generatedand maintained manually or by machine.

A database has following implicit properties:

a. It represents some aspect of the real world, sometimes called the miniworld or the Universeof Discourse (UoD). Changes to the miniworld are reflected in the database.

b. It is a logically coherent colletion of data with some inherent meaning. A randomassortment of data cannot correctly be referred to as a database.

c. A database is designed, built and populated with data for a specific purpose. It has anintended group of users and some preconceived applications in which these users areinterested.

DATA BASE MANAGEMENT SYSTEM :

Data base management system is used to build and manage the database i.e. add, change(edit), delete and sort (arrange in order ) information in the data base, to keep data base uptodate. It also helps to retrive information in the desire format from the data base.

In general, a data base consists of units called records, defined by a common structure.

Example :- In a telephone book, a record is a particular persons’s name, address and tele-phone number. Each of the three items is a field.

TELEPHONE BOOK :

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RELATIONAL DATABASE MANAGEMENT SYSTEM :

Some Applications often involve several databases, each holding seperate data. For example,a payroll system might require three of them

FIRST DATA BASE :

The primary one has the number of hours worked by each person on each project.

SECOND DATABASE :

A second one contains projects budgets and expenditures organized by project number.

THIRD DATA BASE :

The third has employee information including identification number, name, salary, location,telephone numbers, and home address.

Now to make records easier to find, we assign unique identification numbers to employeesand projects. Then we can store the ID number in the files rather than a name, for exampleBrown Jim have ID number 14738 and so for all the employees. We can use the ID to get thename or other information from the employee file

Similarly the project numbers links the project file to the payroll. The three files form a RELA-TIONAL SYSTEM using employee and project number as linking fields. This is called asRELATIONAL DATA BASE MANAGEMENT SYSTEM.

Fig 1.1 Shows the relations

Fig 1.1 Relationship in a simple payroll system

FOXPRO

Fox Pro is powerful Database management system with menu driven interface, which givesgreat deals of convenience in creating and handling database. It is also user friendly. Thissoftware can be used to build very complex application for real world applications, such asaccounting inventory, personnel administration, Statistical analysis and information system. Itcan be used to

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Fig 1.2 Microsoft FoxPro for Windows

1. Edit data records when ever required2. Retrive data selectively from stored records to provide specific information.3. Performs calculations.4. Create screens that can interact with the user5. Create menu system to run your frequently used application.6. Enhance reports with graphics and quality fonts.

DIFFERENCE BETWEENDBMS RDBMS

1. Storage, access path and data structures Storage, access paths and data struc-tures can’t managed by DBMS can be managed by RDBMS

2. In DBMS logical and physical view of the In RDBMS only logical view of the database is considered data base is considered.

3. DBMS model can not achieve the RDBMS model can achieve both thestructural and data independence data and structural independence

4. Only single relationship exists in DBMS One is to One, One is to Many andMany is to Many relationship exits inRDBMS

5. System requirement is not so important It requires very powerful and compli-as it can run with simple system configu- cated hardware and operatingration system.

LOGICAL CONCEPT OF DATA BASE :

The logical concept of database focuses on the logical nature of the data representation.Therefore the logical model of a data base is concerned with what is represented in the database rather than how it is represented.

Logical concept of data base include three types of relationship.

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1. ONE TO MANY RELATIONSHIP

The one to many relationship is labeled “ 1 : M” For example, the relationship between thepainter and the paintings is represented as

PA IN T ER 1

PAIN T IN G M

Fig 1.3 - One to Many Relationship

2. MANY TO MANY RELATIONSHIP :

The many to many relationship is labeled “ M : N”. For example, the relationship betweenemployee and the job skills is represented as shown below.

EM PLO YEE M

SKILL N

Fig 1.4 - Many to Many Relationship

3. ONE TO ONE RELATIONSHIP :

The one to one relationship is labeled “1:1”. For example, the relationship between the em-ployee and the not dog stand is represented as shown in fig 1.5.

S TA N D 1

E M P LO Y E E 1

Fig 1.5 - One to One RelationshipNOTE : For many relationship double arrow head is shown and for single relationship only single arrow head

is shown.

ASSIMILATION EXERCISE

Q.1 What do you mean by a database ?

Q.2 What are the key differences between DBMS and RDBMS ?

Q.3 Explain the logical nature of data representation and compare the various relationships?

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CHAPTER - 2

DATABASE CREATION, ITS HANDLINGAND REPORT GENERATION

CREATING AND MAINTAINING DATABASE FILE

Creating Data Table:

Let us suppose that you have to create data table for a institute which is givinig educationto the students in computers. The institute wants to keep records of student to track over allperformance.

A data table is made up of series of information for each students stored in separate record.Itis important that information is broken down systematically into different items or fields,sothat you can successfully retrived the stored information whenever needed.

According to above example the table structure may have the following fields.

Reg.No. Student name adm_Date Course Examdate Result

Each field of table structures is defined by four parameters the field name, type, width & index.

Field name: Each field must have unique name for its proper identification.

Rules for giving field name:

l It must contain maximum 10 characters may be alphabets A-Z, numerals 0-9 & theunder score ( _ ) may be in uppercase.

l First character of field name must be an alphabet.l Blank space, punctuation marks are not allowed for field name.

It is good practice to give meaningful field name, so that it indicates nature of the contentsof the field.

For example the database create the following structure:

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Field Name Description

1) Reg_no. Students Registration number

2) Stud_Name Students Name, with father’s name surname

3) Date_add Date of Admission

4) Cou_name Course Name

5) Exam_dt Date of Exam

6) Result Result of Exam

7) Remarks Memo field for putting remarks of particular student

Field types & width

The field type determines the type of data that you can enter. The field width determines howmuch space will be allocated for storing data.

l Character: The character fields can be used to store letters, numbers, special symbols& blank space. The maximum field width of a character field is 254.Thedefault width is 10.

l Numeric: The numeric fields can be used to store numbers on which calculationscan be performed. The maximum field width of a numeric field is20,including an optional plus/minus sign and decimal place. The defaultwidth of numeric data is 10.

l Float: The float field is specifically designed for scientific data. There is nodifference between the numeric and float data types and float is includedin Foxpro only for backwards compatibility to database files. The maximumfield width of a float filed is 20, including an optional plus/minus sign .Thedefault width of float data is 10.

l Date: The date fields are used to store dates. The field width of date field isalways eight. The default display format is mm/dd/yy. This can be modifiedto other country formats by using the SET DATE command.

l Logical: The logical fields accepts only single character representing True/Falsevalues. Logical True(.T.) can be entered as T,t or Y (Yes) and Logicalfalse(F) can be entered as F,f or N or n (no).

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l Memo: The memo fields may be used to store any printable ASCII character(letters, number, blank space or special symbols). All memo fields in adatabase memo file extension .dbf, which is created while setting up thedatabase file. Memo fields sizes are limited only by the amount of memoryavailable. Each memo field occupies only ten byte spaces in the table(database).

l General: The general field is used to store OLE (object Linking and Embedding)objects. A Width of 10 characters is automatically assigned. Thiscorresponds to the amount of space used in the table. The general fieldsizes are limited only by the amount of the memory available.

Field Type Field Width Best UsesCharacter Max 254 Character default10 Name,booksNumeric Max 20 Character Default 8 CalculationFloat Same As numeric Scientific CalculationLogical 1 Character Answer Yes/No True/ FalseDate 10 Character DateMemo Any length DescriptionGeneral Not applicable Graphics embedded in data

CREATING A NEW DATABASE FILE

l From file menu, select new, New dialog box appears as in fig. 2.1

Fig. 2.1

l Select table /dbf

l Press New

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l A Structure dialog box appears as in fig 2.2

Fig. 2.2

l Write field name type, width as shown in table press ok.l Foxpro ask “ Input data record now?” as shown in fig 2.3

Fig. 2.3

APPEND COMMAND

To add the record in dbf file (table). The append command is used. Foxpro has two screendisplay modes i.e. change mode and browse mode.

l From record menu select append. Data entry windows, appears as fig. 2.4.

Fig. 2.4

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l Type related data to appropriate field. To move from one field to another press tab.

l After filling one record the cursor append in the first field of next record.

Entering text in Memo field:

l To Enter text in memo field move cursor to memor field, press ctrl + page down. Memoediting window appears is shown in fig.2.5

Fig. 2.5

Window title at the editing windows is Student Remark. Student indicates that remarks is fieldof student.dbf Type the text for this window.

CHECKING SPELLING:

FoxPro has built in spell cheker. To checker spelling follow the following steps.

1. Move the cursor at the begining of memo.2. From text menu choose spelling option, foxpro displays the spelling windows as shown

in fig. 2.

Fig. 2.6

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3. If any mistake occur foxpro displays appropriate option.4. Click on control menu box of editing window & select close option or from text menu

select close option to close editing window.5. Notice that the word “memo” in remark field has changed to Memor indicating that field is

not empty, which is shown in fig 2.7

Fig 2.7

USING BROWSE MODE:

To display browse mode, do the following steps

1. From browse menu select browse option.2. Foxpro display browse window as shown in fig 2.8

Fig. 2.8In browse formatted field name displays as column headings of tables. It displays severalrecords at a time but the screen is not wide enough to display all the fields.

3. To enlarge window use maxmize button.4. To scroll screen horizontally press tab or shift + tab5. Type the record as same as in change mode.6. To close browse window click on the control menu bar of the window & select close option. By

this step all record you have type is saved. or press Ctrl + W

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EDITING RECORDS

To edit a particular record do the following steps.

1. From record menu choose change option, browse window in change mode appears.2. Move the cursor to the record Pointer of which data you want to make the changes.3. To Save changes click on control menu box & select Close option or press Ctrl + W4. To discard changes press esc key.

DELETING RECORDS:

To delete records 5 & 6 from student.dbf follow the following steps.

1. Open student. dbfl From file menu select Open option the Open dialog appears.l Double click on student.dbf the file returns.

ORIn command window type use student & press enter key.

2. Browse the table3. Move the cursor to record 5 drag the mouse until this record highlighted or press down

arrow to this record.4. From Browse menu choose toggle delete option. You can pack the deleted records by

selecting pack option from database menu.5. Recall records 5 by repeating step 2 & 3.

MOVING : Through table

If table have many records to access a particular record by arrow keys is time consuming. Youcan reach target quickly by using goto command.

1. From data base menu select browse option2. From Browse menu select Goto option, Foxpro displays dialog in as fig 2.9

l To move to Top of data table click on top.l To move the bottom of dbf file i.e. at last record press B or click on bottom.l To move to particular record press R or click on record .The text area is highlighted.

Type the number 4 and press “enter”, cursor has moved to 4th record of first field.

Fig. 2.9

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BROWSE WINDOWS

Browse window has the typical features of the system window. In addition to move resize &scroll, it has six other interesting features. Spilt the windows into two, as inl Change active window from the left window to the right window and vice-versa.l Link and unlink the split windows.l One window in Browse mode and other window in change mode or the windows in same

mode. (Fig. 2.10)

Fig. 2.10l Move a data field from one column to another.l Change width of a field.

TO SPLIT WINDOW

1. Click on the window split box at the bottom left corner of the window & drag the mouse toyour right window emerging on the left side as shown in fig .2.11

Fig 2.112. Release the button when the windows are of the sizes you want.

3. Repeat steps 1 & 2 to close the window but with dragging the mouse to the left and then

UNLINK THE SPLIT WINDOW

By defualt the split window are linked one window scroll another window also scroll in thesame way. In unlinked stage records scroll in active window, another window record does notmove.

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To unlink split window:

1. From the Browse menu choose & Link partitions option. This is toggle option

To Move Position of a field

1. Point to fields name

2. Press the Mouse Botton & drag the mouse left or right to the desired position.

3. Release the Mouse button when the field is where you desire.

To Change Field Width

1. Click on vertical grid line on the right hand side of the target field name & drag the mouseleft or right until the field size is what you like.

2. Release the button

TO COPY THE STRUCTURE

To copy the structure to a new file, which will be called TEMP since it is being used onlytemporarily, enter

COPY STRUCTURE TO C:\STUDENT\TEMP

Now to make TEMP, the current file, select File > Open again, select TEMP.DBF from fileName list of the open dialog box and select the open push button

SORTING AND INDEXING:

Foxpro provides two options for sorting database SORT and INDEX.

SORT COMMAND:

If you want your STUDENT.DBF student name to be sorted in alphabetical order, give thefollowing commands

USE STUDENTSORT ON NAME TO S _ NAME

In the above case a new dbf file named s_name is created and is sorted in ascending order(by default). For sorting in descending order enter

SORT ON STUD_NAME / D TO S1 _NAME

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INDEX COMMAND:

In Index command no new file is created it has a extension of IDX.

Syntax :-INDEX ON <field expc> TO (index name>[ASCENDING/ DESCENDING]

MEMORY VARIABLES

Data required for temporary use is not stored in a data base file. Instead, it is stored in amemory variables.

MEMORY VARIABLES :- A CLASSIFICATION

Table shows the variables (memory) used in Foxpro Programming.

TYPE OF MEMORY DESCRIPTION VARIABLES

CHARACTER Size is determined by the number of characters stored init. The maximum limit is 254 Bytes.

NUMERIC No limit on the number of digits that can be stored.

DATE Created by a character to date conversion of a date staredas a character. Size is 8 bytes and is fixed.

TABLE : Foxpro Memory Variables

CREATING AND INITIALISING MEMORY VARIABLES

Table below shows the different ways of initialising memory variables in Foxpro

TYPES OF MEMORY INITIALISATION VARIABLES

NUMERIC STORE 1 TO choice, ctr, ctrlSTORE 11.66 TO varChoice = 1

CHARACTER STORE ‘ABCD’ TO Alpha 1STORE SPACE(5) TO NAMEalpha 1 = “ABCD”

DATE STORE CTOD(“10/03/98”) TO DTDT = CTOD(“10/03/98”)STORE DATE( ) TO C_DTMDT = CTOD (“ / / “)

Table:- Initialisation of Memory Variables.

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The SPACE( ) function initializes character type memory variables with blanks.

STORE :- The store funtion is used to store the charater/numeric variables

SYNTAX

STORE <expr> TO <memory variables list>

where<expr> is an expression<memory variables list> is a list of memory variables.

EXAMPLE:-

1. STORE “ABCD” TO ALPHA2. STORE 1 TO CHOICE, CTR, ICTR3. STORE SPACE (5) TO NAME4. STORE CTOD(“12/10/98”) TO DATE5. STORE DATE( ) TO DATE1

CALCULATION DONE ON MEMORY VARIABLES

Calculations can be done on numeric variables by adding, subtracting, multiplying or dividing.

Similarly, a number may be added to or subtracted from a date type variables or the differencein dates may be computed.

EXAMPLE:-

1. SAL = T_SAL + BASIC + BASIC *.252. T1 = YEAR(D_JOIN)/43. W_YEAR = YEAR(DATE( ))-YEAR(D_JOIN)4. STORE A+1 TO A15. A2 = A2+16. A3 = A3 -7

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MATHMATICAL OPERATORS:

Following are the mathematical operators

OPERATOR DESCRIPTION= Equal to> Greater than> Less than> = Greater than or equal to< > or # or ! = not equal to$ Contained in (applicable only for character data)= = identical to (applicable only for character data)

EXAMPLE

LIST FOR PIN >” 110025"LIST FOR PIN < “ 110026”

LOGICAL OPERATORS

LOGICAL OPERATORS DESCRIPTION

.AND. Action will take place only if each or the conditionsjoined with .AND. are true

.OR. If any one of the conditions joined with an .OR. is true,action will take place

.NOT. Action will take place only if the opposite value of theconditions is true i.e. all the records which do not satisfythe conditions will be valid

EXAMPLE

LIST F_NAME, L_NAME, PHONE, STATE FOR STATE = “ HARYANA” .OR. STATE = “PUNJAB” .AND. NOT. STATE = “MAHARASHTRA”

RELATING DATABASES WITH SET RELATION COMMAND

Linking of two files is done, with command SET RELATION

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EXAMPLE:MASTER .DBF

Field name Type Width DecCode Numeric 4Name Char 15Address Char 18City Char 12Pin Char 6

Enter the following data

CODE NAME ADDRESS CITY PIN

1200 A.K.ARORA G-234,SAKET N.DELHI 110016

1250 G.K.DEB 12,NEW MARKET N.DELHI 110003

1251 S.SRIKANT 12B,PAHARGANJ N.DELHI 110055

1260 RENU SHARMA 17,IIT CAMPUS N.DELHI 110016

Next create another database file

DEPOSIT.DBF

FIELD NAME TYPE WIDTH DECCODE NUMERIC 4 0AMOUNT NUMERIC 7 0DEP_DATE DATE 8PERIOD NUMERIC 5 0RATE NUMERIC 5 2

Enter the records

CODE AMOUNT DEP_DATE PERIOD RATE1250 10000 04/06/98 180 10.01260 5000 03/03/95 45 9.01251 8000 06/06/95 300 10.01260 10000 06/07/98 250 11.0

STEPS :- Enter the following command at command window

USE MASTERINDEX ON CODE TAG CODESELECT 1USE DEPOSITSSELECT 2USE MASTERSET ORDER TO CODE

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The above steps have opened both databases files and have also selected the index on thecommon field CODE

Paraent file ————> DEPOSITS.DBFChild file ————> MASTER.DBF

At command window enter following

SELECT ASELECT 1SELECT DEPOSITSSET RELATION TO CODE INTO BSET RELATION TO CODE INTO MASTERGOTO 2?CODE,B->CODE?CODE,MASTER->CODELIST FIELDS CODE,B->NAME,B->ADDRESS,B->CITY,B->PININDEX ON CODE TAG CODEBROWSE FIELDS CODE,AMOUNT,DEP_DATE,B->NAME

REPORT GENERATION

Before you start the foxpro report writer, create a working environment by opening the necessarytables & indexes & establishing relations the report.

This environment information can be saved in the .frx file.

CREATING A NEW REPORT:

(i) To create a new report form

1. Choose New from file menu.

2. Choose the Report radio button in the new file dialog.

3. Choose OK Report layout window appears or type create report <filename > incommand window.

(ii) Modifying an existing report

To modify an existing report form

1. Choose open from the file menu popup2. Make sure Report appears on the list files of type popup.3. Choose the report form file you want to open from the open dialog or type modify

report <filename> in command window.

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Fig 2.12

A new report layout window has three bands separated by band separation bars. Additionalbands become available when you define groups, title page & summary. Each band cancontain text, table fields, computed fields, calculated values, lines & boxes.

(i) Band Type

(i) Title - The title band contains information that appears before the mainreport. The information contained in the Title band is printed oncefor the entire report.

ii) Page Header - At the top of the each page of the main report is the Page HeaderBand. A page header might include the report title, date, pageno, &so on.

iii) Column Header - If you select more than one column for your report, you have theoption to include a heading at the top of each column.

iv) Group header - When data is grouped, each group can have a group header printedbefore it. These headers indicate the information that is containedwithin each level of grouping

v) Page footer - At the bottom of each page of the main report is the page footerband. It contains report name, date, page no., & so on. It can alsoinclude summary information for data on that page.

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vi) Summary - The summary appears after the main report. It can contain summaryinformation or text that summarizes the contents of the report. It isprinted once per report.

vii) Tool Box - The toolbox is the column of buttons at the left of the report layoutwindow. These tools allow you to create report objects. Followingare the tools available with report writer.

1. Selection Pointer2. Text Tool3. Field Tool4. Line Tool5. Rectangle Tool6. Rounded rectangle tool7. Picture tool

Fig 2.13

1. Selection pointer

(i) To select an object in the report layout window, click the selection pointer then click onthe object select multiple objects, Shift +click on each object. When multiple objects areselected, they act as one object when moved, edited or deleted.

(ii) To deselect all selected objects in the report layout window, position the pointer off theselected objects & click.

(iii) Sizing objects - A selected object has handles, which are small boxes in the corners &on the sides of the objects. To resize the object, point to one of the handles & drag untilthe object is the desired size.

(iv) Deleting object - To delete an object, select it & press backspace or delete.

(v) Changing object attributes - You can change the font type face, fill & color of a selectedobject by choosing menu options from the object menu.

2. Text Tool

i) To add or edit text in your report, click the text tool & click in the report layout windowwhere you want to add or edit text. Make the desired additions or changes.

ii) You can change the font & color of text by selecting the appropriate option on the objectmenu.

iii) Double clicking on a text object with the selection pointer opens the text dialog so youcan determine the text prints, its relative position in a band & add comments.

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iv) Comment - choosing comment allows you add comments to the .frx file. Comments arefor your reference & do not appear anywhere in the printed report.

v) Position relative to - Here you can specify whether the text you have included in the bandretains its position relative to the top of the band or bottom of the band.

vi) Print when- Choosing Print when .. in the text dialog opens the print when dialog so youcan establish exactly when the text is printed in your report.

3. Field Tool

Report can include table fields, variables, calculated values, calculated fields or user definedfunctions.

i) To place a field in a report, click the field tool then click in the Report layout windowwhere you want the field to appear & drag to the desired size.

Choose the Expression... push button to open the expression builder dialog. In theexpression builder you can build an expression or select the fields of a table whichappears in the left side. & verify that it is correct before continuing.

ii) Formatting field - When a valid expression is displayed to the right of the Expression ...push button, you can choose Format.... to display the format dialog so you can specifythe format for the field in your report.

iii) Computed fields - Choose calculate .. in the report expression dialog to open the calculatedialog. Here you can select a mathematical operation to create a computed field. Radiobuttons in the calculate dialog are Nothing Count, Sum Average, Lowest, Highest, Std,Deviation, Varience. At the top of the calculate dialog is the Reset poup control With this,you can select the point at which the value for this field will be set to zero.

When you have made the desired selection &/ or entered the desired values in the appropriateareas of the Report Expression dialog, choose OK to confirm the selections. When you returnto the Report Layout Window, you will see your expression displayed in the Report LayoutWindow. Fields can be sized or mover as desired.

4. Drawing Lines:

To draw a vertical or horizontal line in report, click the line tool, position the pointer where youwant start of the line to be, & drag until the line is of the desired length. To draw a rectangle,clickthe rectangle tool,position the cursor where you want a corner of the rectangle to be & draguntil the line is of the desired length.

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FOXPRO PROGRAMMING

5. Drawing Rectangles

To draw a rectangle, click the rectangle tool, position the cursor where you want a corner ofthe rectangle to be & drag until the rectangles is of the desired size. Double clicking on a lineor a rectangle opens the rectangle / line dialog.

6. Drawing Rounded Rectangles

To draw a rectangles with rounded corners, click the rounded rectangle tool, position thecursor where you want a corner of the rectangle to be and drag until the rounded rectangle isof the desired size.

7. Defining Pictures

You can include individual bitmap pictures or general data fields which can contains a varietyof bitmap pictures & other objects. To define a picture for the report, click the picture tool,position the cursor where you want a conrer of the picture to be, & drag until the picture frameis of the desired size. The report picture dialog opens.

(i) Picture From:

File - choose the File button to open the picture dialog so you can select the desire. BMP fileor you can type the name & path of the BMP file in the text box beside the File button.

Field - To include a general data field in your report choose the field radio button. Choose theField button to open the choose Field/Variable dialog so you can select the desire table field.

(ii) If Picture & Frame Different Size:

Clip picture - If the picture is bigger than the frame you created in the Report Layout Window,clip picture will show a section of the original bitmap in the frame, retaining the picture’soriginal dimensions.

Scale picture - Retain shape - This will display the whole picture, filling as much of the framethat you size in the report layout Window as possible while retaining the relative proportions ofthe bitmap picture.

Scale picture -Fill the frame - Choosing this option will display the whole picutre filling theframe that you size in the screen design window completely.

Centre picture - Checking this option insures that general field pictures smaller than theframe are centered in the frame in the report.

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FOXPRO PROGRAMMING

Report menu

When you start the report writer, a Report menu is added to the menu bar. It has followingoptions.

1. Page Layout.2. Page preview3. Show position4. Ruler/Grid.5. Snap to Grid.6. Title/summary.7. Data grouping.8. Variables.9. Quick Report.

1. Page layout - Choosing this option opens the page layout dialog. The page layout dialogallows you to determine the number & width of columns in your report, the width of theleft margin & space between columns. A modal of the report or layout page displays thecolumn & margin settings.

2. Page preview - Choose this option to display the page preview dalog with a full page oractual size representation of the first page of report. To toggle between the tworepresentation click on the Zoom in or Zoom out.

3. Show/hide -Position this option displays or hides the co ordiantes of the mouse pointer& the dimensions of selected objects in the status bar. By default position is hidden.

4. Ruler /grid - Ruler/Grid opens the Ruler/Grid dialog which allows you to set the units ofmeasurement for the rulers or to change the size of the invisible alignment grid.

5. Title/summary - This option allows you to specify whether a title & or summary bandshould be included in the report. Check New page to issue a page eject after the title barinformation is printed or before the summary band information is printed. choose OK inthe title/summary dialog to return to the report layout window.

6. Data Grouping - Even though sorting or indexing a table causes the record to beprinted in a specified order, many times user want to separate the record into groups.The data grouping option on the report menu allows you to create upto 20 levels ofgroups within groups of data & perform opertions on those groups.

Adding a group band

1. Choose Data Grouping push button from the report menu.2. Choose the Add push button. The Group Info dialog appears.3. Choose the Group push button to bring the expression builder. Create the group

expression in the expression builder & choose OK to return to the Group Info dialog.4. Choose the desired grouping options.

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FOXPRO PROGRAMMING

5. Chosse OK. The group expression is displayed in the data grouping list.

To add more group repeat this process. Groups are numbered in the data grouping list in theorder in which they are created. Group bands can be changed added or deleted by usingcorresponding puch buttons.

7. Variables - Choose variables to display the report variables dialog so you can creatememory variable within a report. memory variables can be used to store the results ofcaluclations performed while the report is being printed.

1. Choose variables in Report menu.2. Choose add push button3. In the variable name text box enter the name for the variable in this text box. We can

assign initial values to the variables reset the variable, specify the calculation for thevariable, delete variable change the order of variables by choosing appropriate options.

8. Quick Report - The quick report option in the report is only avaiable when the detailband of the Report Layout Window is empty.

1. Choose Quick report to open the quick report dialog so you can automatically placeselected fields in the Report Layout window. here you can specify column layout or rowlayout.

i) Title check box determines whether or not field names will be displayed as titles above ornext to the corresponding field.

ii) Field check box shows Field Picker dialog box.iii) Add alias check box automatically adds alias to all field names in the Report Layout

window

Saving the report

1. Choose Save from the file menu to save the report. The first time you save the report youwill be prompted to name the file.

2 If you have not previously saved the environment information, an alert appears asking ifyou want to save the environment information.

Running Reports:

To run reports do one of the following.

1. Choose Report from the Run Menu & select the report definition file you want to use.

2. Type report form <filename> at command window.

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FOXPRO PROGRAMMING

ASSIMILATION EXERCISES

Q.1 What are the various rules and conventions being followed while naming a field inFoxPro ?

Q.2 What are the various field types in FoxPro ?

Q.3 How do we:

a. Add, Edit, Delete records in a DBF file ?

b. Enter text in a menu field ?

Q.4 How do we sort a database in FoxPro ?

Q.5 Explain the significance of Memory Variable in FoxPro, method for their initializationand various operations performed on them.

Q.6 What are the various mathematical and logical operations performed in FoxPro ?

Q.7 Explain the importance of Report generation and how do we create/modify a report ?

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CHAPTER - 3

COMMAND FILES LOOPS & DECISION MAKINGIN STRUCTURE PROGRAMMING

COMMAND FILE

The command MODIFY COMMAND will activates the Foxpro Word Processor. The name forthe program file can be given with this command. For example,

MODIFY COMMAND TEST1

With a default extension of .PRG

SYNTAX :

MODIFY COMMAND <file>where

<file> is the name of the program file.

EXECUTING A PROGRAM:

The DO command executes a program i.e. it executes each command in a program file.

SYNTAX:

DO <FILE>where

<file> is the name of program file

EXAMPLE:DO TEST1

SET TALK COMMAND

When using memory variables FOXPRO shows the results of assigning or changing thevalues of these variables i.e. FOXPRO give response to the user when enter the value of amemory variable is changed. Similarly, the results of commands like DELETE, RECALL,REPLACE, COUNT etc. are displayed on the Screen. The SET TALK OFF command given at

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FOXPRO PROGRAMMING

the command window or in a program, controls the display of such messages. By DefaultTALK is set ON.

EXAMPLE:

Enter following command at command window

MODIFY COMMAND TEST1

Alter pressing return key, FoxPro word Processor will be open. Type following lines

SET TALK ONSTORE 2.6 TO M1WAIT

Save the TEST1. PRG by pressing <CTRL> + <W>

Now at command window type

DO TEST1

and press return key.

At the console 2.6 will be displayed because TALK is set ON.

Now, enterMODIFY COMMAND TEST 2

and enter following lines

SET TALK OFFSTORE 2.6 TO M1WAIT

Save it and run the program.There will be no response because TALK is set OFF.

Some other set commands are

1. SET DATE BRITISH/ AMERICAN2. SET EXACT ON / OFF3. SET CONFIRM ON / OFF4. SET SAFTY ON/ OFF5. SET PRINT ON/ OFF and many more

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FOXPRO PROGRAMMING

WAIT COMMAND

The wait command is used to pause the execution of the program. When Foxpro encountersWait in a program (or you enter WAIT in the command window), it displays a message,

Press Any Key To Continue. . .

CLEAR COMMAND:

The CLEAR command clears the display. On the Screen.

SYNTAX:CLEAR

DECISION MAKING IN PROGRAMS:

1. IF...ELSE...ENDIF:

The IF...ELSE...ENDIF command is fairly straight forward and easy to understand. It takesthe form as under.

IF BASIC > 1000CONV = 500

ELSECONV = 300

ENDIF

In above case if BASIC > 1000, conv. = 500 otherwise conv = 300

SYNTAX:IF <expL>

<Statement>[[ELSE]

<Statements>]ENDIF

where < expL >is a condition

EXPLANATION:

If the < expL > is true, the code following the IF clause is executed. If the expression is nottrue, the code following the ELSE clause is executed.

As the square brackets indicate, you can also use this command without any ELSE clause, inthe form.

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FOXPRO PROGRAMMING

IF < expL > . . . . . .ENDIF

The code will be executed is the expression is true.

NOTE :- EVERY IF HAS A CORRESPONDING ENDIFExample is given below

EXAMPLE:

1. IF BASIC > 2000TAX = 200

ELSEIF BASIC > 600.AND. BASIC < = 2000TAX = 250

ELSETAX = 300

ENDIFENDIF

In the program segment shown above, if the BASIC is not greater than 2000, the programfurther checks if the BASIC is in the range of 600 to 2000. If so, the variable TAX is assignedthe value of 250, otherwise it gets the value 300.

2. IF POST = “DIRECTOR”IF BASIC > 10000

TAX = 1000ELSE

TAX = 300ENDIF

ELSEIF POST = “PRINCIPAL DESIGN ENGINEER”. . .

ENDIFENDIF

In this case, if the POST is DIRECTOR, the program further checks if the BASIC is greaterthan 10000. If both conditions are true, the variable TAX will get the value 1000 otherwise ifBASIC is not greater than 10000, the TAX will be 300.

Since an IF . . . ENDIF construct is nested inside an other IF . . .ENDIF, Such constructs arecalled NESTED IF CONSTRUCTS.

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FOXPRO PROGRAMMING

2. DO CASE . . . ENDCASE:

The program segment using the nested IF...ELSE...ENDIF construct could also be written,using the DO CASE . . . ENDCASE construct, as given below:

DO CASECASE BASIC > 2000

TAX = 200CASE BASIC > 600.AND. BASIC <2000

TAX = 250OTHERWISE

TAX = 300ENDCASE

The DO CASE...ENDCASE construct selects a single course of action from a set of alterna-tives. Any number of mutually exclusive options may be listed between DO CASE and theENDCASE commands.

Each case is evaluated sequentially. As soon as a single CASE statement is found to be true,FOXPRO executes all commands between that CASE statement and the next one. All otherCASE statements and commands within the construct are ignored and processing begins atthe first command after the ENDCASE clouse. IF one of the conditions is found to be true, thecommands after the OTHERWISE clause gets executed. The OTHERWISE clause operatesin the same way as the ELSE clause in the IF statements. The ENDCASE command must beused to mark the end of the DO CASE construct in a program.

PERFORMING REPETITIVE TASKS : LOOPING -

1. DO WHILE ... ENDDO

DO WHILE loop, which has the following form i.e.

SYNTAX:

DO WHILE < expL > . . . . . .

ENDDOwhere < expL > is a condition

The DO WHILE . . . ENDDO construct allows statements to be executed repeatedly as longas a given condition is true.

EXAMPLE:

C.E.D.T. Gkp. has to print a list of the company providing components of which 5 copies arerequired.

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FOXPRO PROGRAMMING

Following is the solution:

* * * COMPANY. PRG * * *USE COMPANY. DBFSTORE 0 TO PRINTDO WHILE PRINT < 5LIST TO PRINTPRINT = PRINT+1ENDDO

The variable PRINT keeps a count of the number of copies printed. The DO WHILE . . .ENDDO construct specifies a loop that continues until the condition ( PRINT < 5 ) becomesfalse. On encountering an ENDDO, control is passed back to the DO WHILE statement andthe condition is checked once again. If the condition is still true, the statement in the loop arerepeated. So, in the above program, the loop will end when the value of PRINT becomesequal to 5.

2. FOR — ENDFOR:

The FOR . . . ENDFOR executes a set of statements within a loop a specified number oftimes. A memory variable or an array element is used as a counter to specify how many timesthe statements inside the loop are executed. Consider the following DO WHILE . . . ENDDOprogram to display logarithm of numbers 100 through 110 that we discussed

STORE 100 TO NUMBERDO WHILE NUMBER < 111? LOG (NUMBER)NUMBER = NUMBER +1ENDDO

The same program can be written with a FOR - ENDFOR loop in the following way:

FOR NUMBER = 100 TO 110? LOG (NUMBER)ENDFOREND FOR

By default, FOR . . . ENDFOR increments the counter (memory variable) by 1. However, ifrequired, you can specify the increment rate through the step option with For. For instance,the following program displays the square root of the series - 10, 12, 14, ... 30.

FOR NUMBER = 10 TO 30 STEP 2? SQRT (NUMBER )ENDFOR

NOTE: Like DO WHILE . . . ENDDO, you can also use loop and Exit commands within FOR. . . ENDFOR.

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3. SCAN . . . ENDSCAN:

SCAN . . . ENDSCAN is another very powerful structure. A condition is specified with SCANand Fox Pro executes the commands included within SCAN and ENDSCAN on all records ofthe current database that meet the condition. For example, let us see how SCAN . . . ENDSCANcan be used to get mailing address labels for a particular city. Consider the following programshown below.

USE ADDRESSACCEPT “ Enter name of City “ TO CHK_CITYSCAN FOR CITY = CFK_CITY? NAME? LOCALITY? TRIM (CITY), PIN?END SCAN

4. TEXT. . . ENDTEXT :

If a screen contains a lot of display matter, instead of giving a number of @ SAY Statements,the actual display desired can be put within TEXT and ENDTEXT statements. When FoxProencounters the TEXT commands, it displays the lines following it until ENDTEXT is encoun-tered.

Example:

The following example shows how TEXT... ENDTEXT can be used to display a menu.

CLEARTEXT1> ADD a new record2> DELETE a new record3> EDIT a record4> EXITENTER CHOICE 1,2,3,4ENDTEXT@ 20,20 GET CHOICE

READ

All the lines within TEXT...ENDTEXT are dIsplayed as they are, on the screen, includingblank lines, if any.

INPUT & OUTPUT STATEMENT:

The @ . . . SAY statements allow designing customised formats for screens and reports.For example, consider the following screen format.

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FOXPRO PROGRAMMING

Fig 3.1: Customised screen formats

To display this on the Screen, the command systax is

SYNTAX:

@ < ROW >, < COLUMN > SAY < EXPR >where

< expr > is an expression

COLUMN

Fig. 3.2 : Showing Rows & Columns Co-ordinates

The rows are numbered from top to bottom. The first(top) row is 0 and the last row is 24. Thecolumns are numbered from 0 though 79 from left to right.

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FOXPRO PROGRAMMING

EXAMPLE:

Suppose we have to display data at row No. 7 and coloum No. 30 than we have

@ 7, 30 SAY “NAME”

Thus at Screen NAME will be printed at ROW 7 and column 30.

DFFINING SCREEN COORDINATES IN USER WINDOW:

If a user defined window is active, all @ commands are routed to that window. In that case,the coordinates used with @ commands are with reference to the top-left corner of the win-dow and not the physical screen coordinates. To experiment with @ commands in a window,enter the following commands:

CLEARDEFINE WINDOW TEST FROM 5, 15 TO 15, 60ACTIVATE WINDOW TEST@ 0,0 SAY “Position 0,0 in Window”

Screen will be as below

Fig 3.3 : User-defined Window

SYNTAX: For defining window

DEFINE WINDOW < file > FROM < R,C > TO < R,C > DOUBLE/PANEL/NONE

Where

R employs Row

C employs Column

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FOXPRO PROGRAMMING

DOUBLE :- defines a double line border

PANEL :- defines a solid border

NONE :- if we donot want to use any border

NOTE :- if nothing is given single border line window is drawn.

SYNTAX:- For activating window

ACTIVATE WINDOW <file>

SYNTAX:- For deactivating window

DEACTIVATE WINDOW <file>

Now finally returning to the point, the commands are:

@ 3, 20 SAY “STORE DEPTT.”@ 5, 10 SAY “LIST OF EMPLOYEES CURRENTLY WORKING”

Now Director C.E.D.T.I. . wants to design a Screen that displays the details of employees in thefollowing format:

EMPLOYEE DETAILS

EMPLOYEE NO : 0001 NAME : MONI PANDEY

DESIGNATION : MANAGER DEPARTMENT : ACCTS

DATE OF BIRTH : 03/03/70 BASIC : 5000

HRA AMOUNT : 2000.00 CONVEYANCE : 600.00

Following is the solution to above Problem:

@ 2, 20 SAY “EMPLOYEE DETAILS”@ 4, 5 SAY “ EMPLOYEE NO: “@ 4, 21 SAY EMP_NO@ 4, 20 SAY “NAME :”@ 4, 48 SAY EMP_NAME

.

.@ 8,5 SAY “DATE OF BIRTH”@ 8, 21 SAY D O B

.

.@ 10, 20 SAY “ HRA AMOUNT : “@ 10, 30 SAY BASIC *.25

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To avoid this tedious process, we can display more than one value in a single line with a single @ ...SAY command by using ‘+’ sign

@ 2,20 SAY “EMPLOYEE DETAILS”@ 4,5 SAY “EMPLOYEE NO. : “ + EMP_NO@ 4,40 SAY “name :” +EMP_NAME

NOTE : When combining expressions/values with a ‘+’ sign, each value must be repre-sented as a character type. For example:

@ 8,5 SAY “DATE OF BIRTH :” + DTOC(dob)@ 8,40 SAY “ BSIC(Rs) :” + STR(basic, 7,2)@ 10,5 SAY “HRA AMOUNT :” + STR(basic *.25, 7,2)

NOTE:- That numeric or date types are converted to character type only if they have to becombined with an other type, using the ‘+’ sign.

INPUT FROM THE USER THROUGH KEYBOARD:

Consider a situation where a list of records of either the Accounts or the Store department isto be printed, based on the value of a CHOICE. Now let us see how the user can input hisCHOICE through key board, in response to a message displayed on the screen.

@ 10,10 SAY “ENTER CHOICE, 1 = Accts 2 = STORES”@ 10, 50 GET choiceREAD

The @ SAY and GET command specifies the position on the screen, where the value typedfrom the key board is to be accepted. The READ command accepts this value into the vari-able.

The @ SAY and GET statements can be combined as follows:

@ 10,15 SAY “ENTER CHOICE 1 = Accts,2 = STORES” GET ChoiceREAD

PROCESSING OF ALL RECORD FROM A DBF FILE

Let us see how the DO WHILE ... ENDDO loop helps in processing records of file. DirectorC.E.D.T.I. Gkp. wants to use the employee Details Screen (refer Fig.1.7) to view the recordsof all the employees.

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Following is the solution :

To do this, the @ . . . SAY Statements have to be executed for each record in the employeemaster file. This can be done by using a looping construct in the program code.

USE EMP_MASTDO WHILE .NOT. EOF( )

. . .

. . . (@ SAY STATEMENT)

. . .SKIP

ENDDO

EXPLANATION:

When the file is opened the record painter is positioned at the first record. The loop isentered and the first record is displayed. The SKIP Command moves the record pointer tothe next record. The end of file (EOF) is reached when the record pointer is placed after thelast record. The statements in the loop are executed as long as end of file is not encoun-tered, i.e. as long as the condition .NOT. EOF ( ) is true

SYNTAX:

DO WHILE < expL >< Statements >

where< expL > is a condition

PROCESSING: A GROUP OF RECORD

We just saw how the DO WHILE . . . ENDDO loop displayed the details of all the employeerecords in the EMP_MAST.DBF file. Suppose the employee details are required for only asingle department-stores. This implies that the records pertaining to stores have to be searchedfrom the file EMP_MAST.DBF file. This file is indexed on the field DEPT, all the records for aparticular department will be arranged togeter thus, only the first record for that department isto be searched..

USING “SEEK” COMMAND FOR SEARCHING RECORDS:

The SEEK command searches for specific records in an indexed file.USE emp_mast INDEX depSEEK “STORES”DO WHILE dept = “STORE” .AND . . NOT. EOF ( )

.

.

.SKIPENDDO

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FOXPRO PROGRAMMING

EXPLANATION:

In this program segment, SEEK searches the index of EMP_MAST. DBF, i.e. DEP.IDX, tofind the first record where DEPT is “STORES”. This record is processed and then SKIPpositions the record pointer at the next record for which the department is stores.

This record is processed and then SKIP positions the record pointer at the next record forwhich the department is stores

SYNTAX:

SEEK < exps >where

< expr >is the expression to be searched

NOTE: The database must be indexed on this expression.

USING “LOCATE” COMMAND FOR SEARCHNG RECORDS:

If the file is not indexed on the desired field/expression, or the recorde to be searched for arevery few in number the LOLATE command can be used to search for the records.

For example;

USE EMP_MASTLOCATE FOR BASIC > 100DO WHILE. NOT. EOF ( )...CONTINUEENDDO

EMP_MAST. DBF is not indexed on BASIC. So, the LOCATE command is used to find thefirst recrod in the file that contains BASIC greater than Rs. 4000. The CONTINUE commandfinds the next record in the file that meets the given condition. This search process continuestill the file reaches the end.

MENU DRIVEN PROGRAMS:

A menu program displays a list of tasks to be done and the user can select one of these tasks.These programs are user friendly, since they are easy to use. In fact, the user need not knowthe program for executing a particular option.

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System File Edit Database Record Program Window Run

C.E.D.T.I. GKP

DEPARTMENT WISE EMPLOYEE INFORMATION

1. ACCOUNTS

2. STORES

3. PERSONNEL

4. SALES

Enter your choice -

Fig 3.4 : Customized Screen Format

The RANGE option used with GET commands for getting only particular menu

@ 16, 10 SAY “ENTER YOUR CHOICE”GET M_NUM RANGE 1,4

READ

If the user does not enter the number in the given range i.e. (1-4), a message “RANGE: 1 TO4 (press SPACE)” appears on the Screen.

SYNTAX:-

GET <var> [RANGE [< expN1 >], [< exp N2 >]]where

<exp N1> is the lower Limit<exp N2> is the upper Limit

The RANGE Option can be given only for numeric and date type fields.

INTEGRATING THE SUB-PROGRAMMES:

Let us see how menu programmes are used to integrate sub-programmes. After acceptingthe choice as a number, the appropriate sub-program has to be executed. This is done asfollows:

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IF CHOICE = 1DO ACCT

ELSEIF CHOICE = 2

DO STORE. . .. . .. . .ENDIF

Here, the sub program ACC.PRG and STOR.PRG will get executed.After a sub-programm isexecuted,control has to be passed back to the main or parent programm with the RETURNstatement.

SEEK “ACCTS”. . .. . .. . .RETURN

LIGHT BAR MENUS DESIGNING

Fox Pro provides another method of designing menus, in which, the menu options, referred toas Menu Prompts are selected by moving a high light bar.Such menus are called Light-barmenus and are attractive and are easy to use. This is because the user can select an optionby just pointing to it rather than entering a value from the keyboard. The high light bar move-ments are controlled by the arrow keys. An option is selected by either typing the first charac-ter of the prompt or by pressing the < ENTER > key. Fig.3.5 shows a light-bar menu. Thefollowing program segment shows the menu required

@ 2, 20 SAY “C.E.D.T.I. “.@ 4, 5 SAY “DEPARTMENT-WISE EMPLOYEE INFORMATION”@ 6, 10 PROMPT “ACCOUNTS”@ 8, 10 PROMPT “STORES”@ 10, 10 PROMPT “SALES”

MENU TO M_NUM

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Output screen is as shown below.

C.E.D.T.I. GKP.DEPARTMENTWISE EMPLOYEE INFORMATION

ACCOUNTS

STORES

PERSONNEL

SALES

SALES Fig 3.5 : Light Bar Menus

EXPLANATION:

The @ . . . PROMPT commands display the menu options at designated positions on theScreen. The MENU TO command invokes a light-bar menu, controlled by cursor keys. As theuser navigates through the menu, each Option is highlighted. On selecting an option, thevariables specified with the MENU TO command (in this case, M_NUM) is created and gets anumeric value depending on the order of the prompts.

SYNTAX:

MENU TO < memory variable >where

< memory variable > is the variable to accept the menu option.

The MESSAGE option of the @ . . . PROMPT command, displays messages on a specifiedrow, to help the user choose on option.

SET MESSAGE TO 20@ 6, 10 PROMPT “ACCOUNTS” MESSAGE

“Display records for Accounts department”

These commands will display the message “Display records for Accounts department” onrow 20.

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SYNTAX:

@ < row >, < col > PROMPT < expc >[MESSAGE < expc > ]

where< expc > is a character

FUNCTIONS:

1. UPPER(<expc>):

Where <expc> is a character expression.

This function returns the upper-case value of the character string or varriable

2. LOWER (<expc>):

This functions returns the lower case value of the character string or varriable.

Example:ANS=”y”

1.DOWHILE UPPER(ANS)=”y”

ANS=”T”2.DOWHILE LOWER(ANS)=”T”

3. VALID (<expc>):

The valid command is used to check whether the data entered into a variable is valid orinvalid.

The operation is similar to that of the range clause the only disfference being that it can beused to validate all data types and complex conditions.

EXAMPLE :

In order to validate is the length of NAME is grater than O,the command is

@ 5,5 say “ENTER NAME”GET NAMEVALID (LEN(TRIM(LTRIM)))>OREAD

Explanation:

In above case the variable will accepted untill name is found to be valid. The only disadvan-tage of the VALID command is that the user cannot specify his oven error messages becausethe VALID command gives an error message of its oven.

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FOXPRO PROGRAMMING

4. TRIM( ):

The TRIM ( ) FUNCTION REMOVES ANY TRAILING BLANKS.

Syntax:TRIM (< expc >)

where < expc > is a character expression.

5. LTRIM( ):

The LTRIM( ) is used to remove the loading blanks.

Syntax:LTRIM(<expc>)

where < expc > is a character expression.

6. RTRIM( ):

The RTRIM is used to remove the trailing blanks.

Syntax:RTRIM (< expc >)

where < expc > is a character expression.

7. ALLTRIM( ):

The ALTRIM( ) command is used to remove all the loading and trailing blank.

Syntax:ALLTRIM (< expc >)

where < expc > is a character expression

8. LEN( ):

LEN( ) returns the length of a specified character expression.

Syntax:LEN (< expc >)

where < expc > is character expression.

Example:CH = “RAJAN”?LEN(CH)

5

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FOXPRO PROGRAMMING

9. SUBSTR( ):

Suppose for a memory variable MITEM_CODE the first 4 characters must be alphabets andthe next(and Last) 2 characters should be digits whose value is greater than 1 but less than10. The user has to enter the MITEM_CODE repatedly as long as these conditions are notsatisfied.

The validation is done using the SUBSTR( ) and the VAL( ) functions. The last two digits areextracted using the SUBSTR( ) function and then they are converted to a numeric value usingthe VAL( ) function.

Example:

In the following example, the extracted word(string) starts at the third character and continuesfor 4 characters:

IF SUBSTR(“ABCAME LOT, 3,4) = “CAME”:

Syntax:SUBSTR(< expc >), < Start >, [ < num_Char >])

where< expc > is a character expression< start > is the stating position< num_char > is the number of characters to be extracted.

10. VAL( )

The VAL( ) function is used to convert a character variable or constant that contains digits toa numeric value. In the following example C_VAR is a character variable:

STORE “133” TO C_VARIF VAL ( C_VAR ) = 133

::

Syntax:VAL(< expc >)

where(< expc >) is a character expression.

11. RECCOUNT ( ):

The RECCOUNT ( ) returns the number of records in the active database file. If there is noactive database file in the currently selected work area, RECCOUNT ( ) returns a zero. Forexample,

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USE i_mast?RECCOUNT ( )20

RECCOUNT( ) supports an optional parameter which indicates the workarea to which thefunction is to be applied. For example, to get the number of records in the file from workareaB, which is the second workarea, the command is

?RECCOUNT (2)10

12. FCOUNT ( ) :

The Fcount ( ) returns the number of fields in the active database file. For example

USE i _ mast? FCOUNT ( )4

Like the RECCOUNT ( ) function, FCOUNT ( ) supports an optional parameter which indi-cates the workarea of the file to which the function is to be appliedd. For example, to see thenumber of fields in I _ TRAN. DBF in workarea B, the command is

?FCOUNT (2)7

13. RECNO ( ):

The RECNO ( ) function returns the current record number, which is the physical position of arecord in the active database file. For example,

USE i _ mast?RECNO ( )1

RECNO ( ) also supports an optional parameter which indicates the workarea to which thefunction is to be applied.

CREATING A PROCEDURE

A procedure is like any FoxPro program except that it begins with a PROCEDURE statementto name it.Procedures can have any valid FoxPro name.Generally a meaningful one thatdescribes the purpose is best.

The last line in PROCEDURE is a RETURN staement..It indicates the end of the procedureand returns control to the caller.Although a procedure can have several RETURNs, goodcoding avoids multiple exit points.

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After testing the procedures, group them into one module. To access them, use the SETPROCEDURE TO command to tell FoxPro the file names where they are stored. We caneven store procedures with the main program by placing them after it.

CALLING A PROCEDURE:

DO calls a procedure the form is

Do <procedure name>

When FoxPro finds the procedure, it executes there until it reaches a RETURN. RETURNmakes it exit and return control to the caller. execution resumes at the line immediately afterthe DO

Following program illustrate the flow of control for a program calling a procedure.

* Main Program<commands>DO dispForm<Commands>QUITprocedure dispform<Procedure commands>RETURN

EXITING PROCEDURE:

The normal way to exit a procedure is via a RETURN statement. Execution continues at theline immediately after the calling DO.

The following four command are used to exit from the procedure

1. CANCEL

2. QUIT

3. RETURN TO MASTER

4. SUSPEND

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EXAMPLE

*Main program<Commands>DO Proced _1<Commands>QUIT

PROCEDURE Proced _ 1 RETURN TO MASTER returns to the highest<Proced _1 commands> procedure call. This is the DO command in theDO proced _2 main program that initiated the series of calls to<Proced _1 Command> reach procedure proced _2RETURN

PROCEDURE PROCED _2< Proced _ 2 commands>If ConditionRETURN TO MASTER _ENDIF<proced _2 commands>RETURN

ASSIMILATION EXERCISE

Q.1 Suppose you want to make a small FoxPro program. Give the general syntax of initializingthe program file with .PRG extension and after typing in your program, by whichcommand you will be able to run it ?

Q.2 What is wrong with the following program:If Choice = A

do mainelse

do not_mainQ.3 What is the function of DOCASE ...... ENDCASE loop ?Q.4 You have made a database file namely ADDRESS.DBF in which the fields NAME,

PHONE_NO stores the names and phone nos. of all your friends respectively. Now, fillin the blanks with a FoxPro command in the following program to search for a name“Deepak” and also display his phone number.

use AddressAccept “Enter name to search :” to s_name........................... NAME = s_name................ * Display Name *................ * Display Phone Number *........................... * End of Loop *

Q.5 Design the following format using @.....Say command starting from 10th row:WELCOME TOMY HOME

Q.6 A dbf file contains one word starting from each alphabet. How will you search for theword starting with “P” ?

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SECTION - B

COMPETENCY OBJECTIVES

The objective of this Section is to introduce the students to the various enhance features ofFoxPro. At the end of this section, a student should be able to :-

v Create Screens and add objects to screens.v Develop application projects and create EXE files.v Carry out relational query by example.v Use object linking and embedding.

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CHAPTER - 4

SCREEN GENERATION & OBJECT ADDING

SCREEN CREATION

You create screens in the familiar way: Select File, New. Select the Screen radio button, andselect the New (or OK) push button to generate the command CREATE SCREEN Untitled;then name the screen by selecting File Save As. As usual, if you are working from the com-mand window, you can name the screen when you first create it by entering the commandCREATE SCREEN <screen image>. The Screen Builder window is shown in Fig. 4.1, and theicons of the toolbox are labelled.

Fig 4.1

Screen specifications are stored in an ordinary database file with the extension. SCX. Whenyou select Program Generate, FoxPro generates the programming code needed to displaythat screen, which is kept in a file with the extension. SPR. This file is an ordinary FoxProprogram, like the ones you wrote in PRG files, and you use it with the usual command DO<filename>. Because it does not have the default. PRG extension, you must enter the com-plete file name to run it. For example, DO SCREEN1.SPR.

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Edit Regions:

To add an edit region, select the edit region tool and then click-and-drag on the screen layoutto place the edit region. When you release the mouse button, FoxPro displays the Edit Re-gion dialog box, shown in Figure 4.2

Fig 4.2

Push Buttons

An asterisk is the specification code for a push button. Its picture function must begin with anasterisk followed by a list of the prompts used in the push buttons being created. For ex-ample, to create two push buttons with the prompts OK and Cancel, you can use the clausePICTURE ‘@*OK; Cancel’. FoxPro adds the angle brackets around the prompts that arelisted. Fig. 4.3.

In the basic form of the command—@<row, col> GET <var> FUNCTION <char exp> IPICTURE <char exp>

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Fig. 4.3

Radio Buttons:

*R is the specification code for a radio button. Its picture function must begin with *R followedby a list of the prompts used in the radio buttons being created. For example, to create threeradio buttons with the prompts Upper, Proper, and Lower (which you can use to determinecapitalization), you can use the clause PICTURE ‘@*R Upper; Proper; Lower’ or the equiva-lent clause beginning with FUNCTION. You can define hot keys for radio buttons as you dofor push buttons, by putting <before a leter of the prompt.

The basic form of the command@ <row, col> GET <var> FUNCTION <char exp>IPICTURE <char exp>

Fig. 4.4

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Check Boxes:

*C is the specification code for a check box. Its picture function consists of *C followed by theprompt that the check box uses. For example, to create a check box that capitalizes text, youcan use the clause PICTURE ‘@*C Capitalize’ or the equivalent clause using FUNCTION.This command can have only a single prompt. You can give it a hot key oin the usual way, byputting\<before one of the letters of the prompt.

Fig. 4.5In the basic form of the command

@ <row, col> GET <var> FUNCTION <char exp>IPICTURE <char exp>

Popup Controls:

A caret(^) is the specification code for a popup control, and it is followed by a list of the optionsthe popup displays. For example, to create a popup control to let the user choose among fourdata types, you can use the clause PICTURE ‘@^Character;Number;Date;Logical’ or theequivalent FUNCTION clause. Since there are often more options to a popup than you wantto list, you can use the optional clause FROM <array name> to read them from an arrayinstead.

Fig. 4.6

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In the basic form of the command@ <row, col> GET <var> FUNCTION <char exp>IPICTURE <char exp>

Adding Object to the Screen:

When you select the text tool, the pointer becomes an insertion bar, and you can click any-where in the screen layout to place a cursor there and type new text or edit text that is alreadythere. Select the selection pointer tool when you are done editing to return the pointer to itsnormal form.

Fig. 4.7

You can specify the font, justification, and spacing of text, as in reports, by selecting Objectfont to display the familiar Font dialog box or by selecting Object > Text Alignment to displaya submenu that lets you select text justification and spacing. Figure 4.7, which lets you entera comment for your own purposes.

Lines, Rectangles, and Round Rectangles:

As in reports, you can place lines, rectangles, or round rectangles in screens simply by click-ing the appropriate tool in the toolbox and clicking-and-dragging to place the object in thescreen.

After you have created these objects, you can use their dialog boxes by double-clicking them.The line and rectangle (like text objects) simply display the Comment dialog box, which letsyou enter a comment for your own purposes. The round rectangle displays the dialog boxshown in Figure 4.8, which lets you select the style(degree of roundness), just as you done inreports.

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Fig. 4.8

These dialog boxes do not control the thickness of the lines used to draw these objects. Tochange the thickness or style of lines, select the object and then select Object > Peri.

This selection generates the command @ <row>,<column> TO <row>, <column>, which drawsa box with the first row and column specified as the upper-left corner and the second row andcolumn as the lower-right corner.

Fields:

To place a field, click the field tool and click a location on the screen in FoxPro for Windows(or move the cursor to the location and select Screen Field in FoxPro for DOS) to display theField dialog box, shown in Figure 4.9. This dialog box lets you place fields, field expressions,or memory variables on the screen and control their features.

Typically, the Input Field (Get) radio button is selected, and this dialog box generates theordinary @ ... GET <var> with a field name as the variable that is displayed. This field canbe edited when the READ command is executed.

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Fig. 4.9

When the Output Field (Say) radio button is selected, most options in the dialog box aredisabled. You can use the Output push button to select the variable to be displayed, and youcan use the Comment push button and refresh check box. The other options are dimmed, asthey do not apply when a variable is just being displayed and cannot be edited.

If the Say radio button is selected, however, it generates the command @ ... SAY <var>,which simply displays the contents of the variable and ‘do’ not let the user edit it.

ASSIMILATION EXERCISE

Q.1 How do we create screens in FoxPro ?

Q.2 Briefly describe the following and method of implementing them :

a. Edit regions

b. Push Button

c. Radio Button

d. Check Box

e. Pop up Control

Q.3 What are the various static objects available for screen building in FoxPro ?

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CHAPTER - 5

RELATIONAL QUERY BY EXAMPLE

Relational Query By Example (RQBE)

The process of extracting specific information is called querying . the FoxPro, querying facilityis called RQBE, which stands for Relational query By Example

l Relational refers to the ability of use several tables with common fieldsl Query means to question or to enquire.l By Example is the way that you ask question such as “Can you tell me how many

companies are located in California?’

Simple Query

RQBE allows you to query your data in many different ways. It makes querying both quickand easy. To begin, open the RQBE window.

Choose Open .... from the file menu.

In the Open dialog that appears, select C:\FOXPRO\TUTORIAL\ in the Directory list.

Select CUSTOMER. DBF and Open. Choose New .... from the file menu.

In the New dialog, choose the Query radio button.then choose the New push button.

The RQBE window appears as shown in Figure5.1.

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Fig. 5.1

Special Query:

You can use RQBE to display only specific fields specifying output fields for a query.

1. In RQBE, window choose the fields .... check box . The RQBE select fields dialogappears.

2. Choose remove all to clear the selected output list.3. Move customer, company to the selected output list. To move the field select it in the

Table fields list and then choose move.4. Repeat step 3 for the following customer fields in the following order : contact, phone,

city state and YTDPURCH, The RQBE select fields dialog .5. Choose OK the selected fields are displayed in the output fields list in the RQBE window.

When you do the query, the fields in the Browse window appears in the order in which theywere chosen in the RQBE window.

Doing the query

1. Choose do query in the RQBE window2. If necessary, size the Browse window

Ordering a query

You can specify the order in which data is presented. For instance, you can display date,alphabetically by City Ordering fields in a query.

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1. Choose the order by... check box in the RQBE window2. In RQUB order by dialog, move customer city to the ordering list to move the field select

it from the selected output list, the choose move3. Choose OK to return to the RQBE window.4. Do the query

Specifying selection condition

To extract only specific record field, you specify selection conditions. Selection conditionstells FoxPro the requirements a record must meet in order to be included in the query output.Each selection condition consists of a field from a table, a comparison item, & a value to becompared with the field contents.

Specifying selection conditions

1. In the RQBE window, click on the rectangle below field name to display the field namepopup select Customer State.

2. Type OH in the text box below example be seen both letters a capitalize.3. Do the query.

You have created a selection condition to view only those records for companies on Ohio. Inthe same manner, popup controls to create multiple rows in the selection criteria area of thisdialog.

The selection conditions you have entered requires the STATE field to look like “OH” STATEis the field, like is the comparison item, & “OH” is the value being compared to the fieldcontents. Like specifies that CUSTOMER, STATE must match “OH” is the value being com-pared to the field contents. Like specifies that CUSTOMER, STATE must match “OH” for arecord to be displayed.

ASSIMILATION EXERCISE

Q.1 RQBE stands for :

Relational Query By Extension [ ] Revolving Query By Example [ ]

Regional Query By Example [ ] None of these [ ]

Q.2 How do you select fields for a query and do the query using RQBE ?

Q.3 How can you specify the way or the order in which the data is presented ?

Q.4 How do you specify the selection conditions in RQBE ?

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CHAPTER - 6

OBJECT LINKING AND EMBEDDING

INTRODUCTION

The ability to cut and paste information from one application to another is a basic feature ofthe window environment. For example we can include a picture from PC Paint Brush in adatabase and, by double clicking on it, open a Paint Brush session to edit it.

The links defined by Windows make OLE differ from simple cut-and-paste. Many Windowsapplications share and exchange information through object links. A link connects a sourcedocument that original object to destination document that uses it. Objects are anything wecan copy to the clipboard. Examples include sound, clipart, animation, business charts,spreadsheets and documents.

We can further specify the connection between an object and its new location as linking orembedding. A linked object does not move.

Example below replaces the @...SAY command with MODIFY GENERAL allowing to modifythe OLE object by double clicking on it.

Example:* Display an OLE picture and allow user to edit itCLEAR*Open databases and find record with pictureUSE STATESSET ORDER TO STATESEEK”FL”* Define picture windowDEFINE WINDOW PICWIN FROM 5,5 TO 20,20FONT “MS Sans Serif,10,B” TITLE states.fullname;CLOSE FLOAT GROW ZOOM* DISPLAY pictureMODIFY GENERAL states.image WINDOW picwin* End of program

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Because we have copied the image as an embedded object. FoxPro knows to open Paintbrushas shown in Figure 6.1

Fig. 6.1

If we change the image (in fig. 6.1 we added the text “Gulf of Mexico”).We must update theembedded version before returning to FoxPro. We can do this by selecting option Update inPaintbrush’s File pull down. However, if we forget or try to exit to FoxPro without updating it,the alert box shown in Fig. 6.2 appears to give us a second chance. If we decide to exit withoutupdating the object, the changes are lost.

Fig. 6.2

We can also use a VERB clause in the @...SAY command to open and edit an OLE object.Verbs consist of numbers or command strings. To determine which ones are valid for OLEservers in your system ,run REGEDIT from the windows Program Manager .It opens a windowwith the title Registration Info

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*Display pictureACTIVATE WINDOW picwin@ 0,0 SAY image

*End of program

Fig. 6.3

In this example FoxPro display the state’s image in the exact size of the original. So we needto know its size to define the window .If the window is too small, the image is truncated. Toolarge and it will appear in the upper left corner with space to its right and beneath it as shownin Fig. 6.3. Someone might ask why Cuba is not visible in the empty area!

On the other hand, we can stretch the image to fill the window completely by adding STRETCHto the @ . . . command.

@ 0,0 SAY STRETCH

Fig. 6.4 shows the result. However, FoxPro may not stretch each dimension equally. Thereforeit may distort the image. The result makes Florida look like Maryland, thus insulting two statessimultaneously!

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Fig 6.4

If we replace STRETCH with ISOMETRIC, FoxPro enlarges the images proportionally in bothdimensions until it reaches a window border. Fig. 6.5 shows the same window as Fig. 6.4 butwith ISOMETRIC. Normally the object would appear only along the left side with a lot of whitespace to its right. However, if we add the CENTER option, FoxPro centers the stretchedimage in the extra space, horizontally in this case.

Fig 6.5

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Note, however, that @. . .SAY does not allow us to edit the object. To do that, we must open itusing the MODIFY GENERAL command.

Moving the original object, even deleting it, has no effect on the copy stored in FoxPro’sgeneral field.

Storing OLE Objects in a General Field:

To add an OLE object to a general field, first open the source or its application and copy it tothe clipboard. Next activate the FoxPro for Windows session or start it from the Project Manager.Open the database where you want to embed or link the object and select the record andgeneral field. Remember, to open a general field, double click on it or press Ctrl-Home.

Next, decide whether to link or embed the object. To link it, select Paste link from the Edit pulldown. To embed it, choose Paste.

We can embed an object without first placing it on the Clipboard. To do so, first open thegeneral field. Then choose Insert Object from the Edit pull down. This open a dialog shownin figure 6.6 that displays a list of all OLE servers. Simply choose one and create the object.When done, exit and FoxPro automatically embeds the entire object file (picture or text) andincludes it in the general field.

Fig. 6.6

Using OLE Fields:

Suppose we have a database containing information about U.S. states with the fields:

ABBREV - state abbreviationFULLNAME - full state nameIMAGE - simple outline picture of the state

The first field stores a two character abbreviation. The second stores the full name. Both fieldsare type character. The third field (of type general) stores a picture of the state created withPC Paintbrush. In previous sections, we learned how to link and embed objects from otherapplications. Therefore, it should pose no problem to create this file. We also mentioned that,in Edit or Browse mode, general fields display the characters Gen or gen and we can showtheir contents by double clicking.

However, we may want a program to displays the OLE object immediately. Program shows theeasiest way to display an OLE picture using a previously defined window.

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* Program* Display an OLE object

CLEAR* Open database and find record with picture

USE statesSET ORDER TO stateSEEK ‘FD’

* Define picture windowDEFINE WINDOW picwin FROM 5,5 TO 30,10 FONT ‘MS Sans Serif, 10, B’ ;TITLE states. Full name;CLOSE FLOAT GROW ZOOM

An embedded object exists twice, once in its original file and once in the new location. If weedit it, we modify only the copy. The original object remains unchanged. In fact, we can deletethe original file without affecting FoxPro’s ability to display or edit the object.

Why Link Objects into FoxPro?

Some obvious reasons for linking objects are:

l To add a company logo to a screen or reportl To add a business chart to a reportl To add a sound clip to a recordl To add a picture to a record (for example, a database of houses for sale)l To include a document rather than a memo field to provide fonts and formatting information

with the text.

Creating an OLE Object

We cannot drop an OLE object anywhere. FoxPro for Windows supports OLE only throughthe General data type. It resembles a memo. In fact, FoxPro stores both in a common file.Besides, while in Edit or Browse, general fields display ‘gen’ when empty and ‘Gen’ when theycontain something. We open general fields by double clicking on them. We can then edit theobject by double clicking on it. If it is a picture, we can even leave the object window open andskip through the database to view its contents in each record. Other OLE objects such assound clips play when opened or may open other applications such as a word processingobject. Imagine a future in which objects could include foul polluting odors, detailed forensicreports with associated film clips, or the kind or window-relating music.

OLE objects are very flexible. They can store sound, pictures, spreadsheets, or text. In fact,each record can store a different object type. For example, FoxPro includes databaseOLETABLE.DBF in directory \SAMPLE\OLE. It contains four OLE objects in each record: apicture, a sound clip, a graph, and a Word for Windows document.

Applications can be OLE clients, servers, or both. A client only accepts objects. For example,because FoxPro accepts objects into general fields, it acts as a client. The application that

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creates them, such as PC Paintbrush, is a server. Some applications can play both roles,creating objects as well as receiving them.

When we add an object to a FoxPro report, we can either link or embed it. If we link it, it doesnot actually become part of the destination. Rather, FoxPro stores a reference or link to it,identifying the application that created it and the directory where it and the application arefound. Later, when we select the object to edit it, FoxPro runs the other application and loadsthe object.

If we embed an object, FoxPro stores both it and a reference to its parent application. Thus wecan edit either without affecting the other. This ability is useful when we must preserve amaster copy of the object while customizing it Editor that provides information about all availableWindows applications. Figure 6.7 shows part of the editor output that defines verbs for theSound Recorder.

Note that this application has two verbs, one to play and one to edit a sound clip.

We can include either the verb number or its text string when using it. For example, to play asound clip, we can use:

@ 0,0 SAY phasers VERB “PLAY”

or

@ 0,0 SAY phasers VERB 0

The latter is obviously better if our aim is to keep anyone from ever deciphering what theprogram does.

Fixing OLE Links

If we lose the link to an OLE object due to moving the file to a new directory, we can recreateit by selecting the Change Link option of the Edit pulldown. This dialog (see Figure 11-8)allows us to find the file anywhere. If the source document was deleted, we can either recreateit before using Change Link, or we can select another one instead.

Convert Link to Static

If we no longer want to let users edit a linked or embedded OLE object, we can sever the linkto the application. Choose Convert to Static (also good for accidentally destroying some ofyour teenager’s particularly awful-sounding or ear-splitting tapes!) from the Edit pulldownmenu. The object remains linked or embedded. However, we cannot double click on it to editit.

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ASSIMILATION EXERCISE

Q.1 Highlight the importance of OLE in application development ?

Q.2 What is the difference between linking and embedding ?

Q.3 How do we implement OLE in FoxPro ?

Q.4 Describe the method for creating and storing OLE objects ?

Q.5 How can we change OLE links ?

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CHAPTER - 7

MAKING APPLICATIONS PROJECT AND EXE FILES

To create a project

Select File > New and select the Project radio button. Select the new push button. Name theproject later by selecting file > save As. Alternatively, use the command CREATE PROJECT<project name>

To add files to the project Manager window

Select the Add push button to display the Add file dialog box, and select the file you want toadd. by default, the first file you add is the main module of the application executed when theapplication starts.

To Work on the files in a project

Highlight a file in the list in the project manager, and select the Edit push button (or simplydouble-click the file) to display the window you use to edit or lay out that file.

To create an application Select the Build push button of the project manager window to display the Build Option dialogbox. Select the Build application radio button to create an APP file that incorporates all thefiles in the project. Select the Build Executable radio button to create a stand alone EXE filethat incorporates all these files. This radio buttons accessible only if you have purchased theFoxPro distribution kit.

To add related files automatically to the Project manager window Select the Build push button to display the Build option dialog box, Select the Rebuild projectdialog box, and FoxPro automatically adds every file called by the files already listed in theproject manager to its list of files. When you make this selection, FoxPro also regenerates thecode for these files.

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To display summary information on the project,

Select the Information push button to display the File Information dialog box, which includescomplete information on all the files of the project. or select project> project Info to display theproject Information dialog box, which includes summary information on the files of the project.

To make a different file , the main file executed when the application begins,

Highlight the file you want to be the main file, and select project > Set Main.

To exclude a file in the project manager from an application,

Highlight the file and select project> Exclude. This allows you to use the project manager tokeep track of files, such as most database and index files. That are related to the applicationbut should not be included in the APP or EXE file that is generated.