Oracle SQL introduction

使用聲明

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Agenda

Database Structure Overview Oracle SQL* Net (Networking) SQL

– Data Retrieval– Data Manipulation Language (DML)– Data Definition Language (DDL)– Transaction Control

Database Objects– Table, Constraint , Sequence , View , Index

DAY 1

Terminology

Instance (SGA + background process) Database (control file + data file + redo files) Tablespace Schema Object

– Table,Index,Sequence,View,Package,Procedure,Function,Cluster…etc

Database Structure Overview

Control Control FileFile

Redo log FilesRedo log Files

Data Data FilesFiles

ParameterParameter FileFile

Archived Archived Log FileLog File

InstanceInstance DatabaseDatabase

SGASGA

SharedSharedPoolPool

LibraryLibraryCacheCache

Data Dict.Data Dict.CacheCache

DatabaseDatabaseBufferBufferCacheCache

Redo logRedo logBufferBuffer

SMONSMON

DBW0DBW0

PMONPMON

CKPTCKPT

LGWRLGWR

ARC0ARC0

UserUserProcessProcess

ServerServerProcessProcess

Stages in Startup and Shutdown

OPENOPEN

MOUNTMOUNT

NOMOUNTNOMOUNT

SHUTDOWNSHUTDOWN

STARTUPSTARTUP

SHUTDOWNSHUTDOWN

How to determine Database up or down ? (Windows)

How to determine Database up or down ? (UNIX)

Database & Tablespace

Tablespace & Database object

Oracle E-Business Suite Tablespace Design

SYSTEM

TEMP

RBS

FNDD FNDX

GLD GLX

OED OEX

Establishing Connections to Oracle Servers

How to determine Listener up or down?(Windows)

How to determine Listener up or down?(Unix)

Starting and using the Net Configuration Assistant

tnsnames.ora

SEMPROD = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.64.32.53 )(PORT = 1520))) (CONNECT_DATA = (SERVICE_NAME = PROD)) )SEMUAT2 = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 10.64.32.54 )(PORT = 1529))) (CONNECT_DATA = (SERVICE_NAME = UAT2)) )

SQL*Plus

Logging into Database

開始 程式集 Oracle 9i Application Development SQL Plus

Logging into Database

SQL*Plus Command Summary (I)

@ & get edit execute host list /

SQL*Plus Command Summary (II)

spool connect describe column set show all exit help

3rd Party Tools

TOAD (Quest Software) SQL Navigator (Quest Software)

Exercise 1

Installation Oracle 9i Database Create Database Connect to Database by SQL* Net (using SQL* Plus) show user

Sample Schema Diagrams

SQL Statement

Data Retrieval– Select

Data Manipulation Language (DML)– Insert,Update,Delete

Data Definition Language (DDL)– Create,alter,drop,rename,truncate

Transaction Control– Commit,rollback,savepoint

Data Control Language (DCL)– Grant,revoke

SQL

Displaying Table Structure

Basic SELECT Statement

SELECT column [alias]FROM table [table alias]WHERE column = ‘xxx’

SELECT column [alias]FROM table [table alias]WHERE column = ‘xxx’

Not Case Sensitive Can be one or more lines Keywords can not be abbreviated or split across

lines

Selecting All Columns, All Rows

Selecting Specific Columns

Arithmetic Expressions

Concatenation Operator

Concatenation Operator

Managing Null Values

NULL is a value that is unavailable,unassigned,unknown,or inapplicable

NULL is not the same as zero or space Arithmetic expressions containing a null value evaluate to NUL

L

Conditions containing NULL

Conditions containing NULL (example)

NVL function

Converts null to an actual value Datatype that can be used are date,character,and nu

mber Datatype must match

– NVL(comm,0)– NVL(hiredate,’01-JAN-97’)– NVL(job,’Not Job Yet’)

NVL Function (example)

DECODE Function

Facilitates conditional inqueries by doing the work of a CASE or IF-THEN-ELSE statement

DECODE (col/express, search1, result1 [ ,search2,result2,……] [, default ])

DECODE (col/express, search1, result1 [ ,search2,result2,……] [, default ])

Using the DECODE Function (example)

Built-in Function Quick Ref.

Preventing the Selection of Duplicate Rows

The default display of queries is all rows including duplicate rows

Eliminate duplicate rows by using DISTINCT in the SELECT clause

SQL>SELECT JOB_ID 2 FROM EMPLOYEES;

SQL>SELECT JOB_ID 2 FROM EMPLOYEES;

SQL>SELECT DISTINCT JOB_ID 2 FROM EMPLOYEES;

SQL>SELECT DISTINCT JOB_ID 2 FROM EMPLOYEES;

Preventing the Selection of Duplicate Rows(example)

SQL>SELECT JOB_ID 2 FROM EMPLOYEES;

JOB_ID--------------------SA_MANSA_REPSA_REPSA_REPSH_CLERKSH_CLERK

SQL>SELECT JOB_ID 2 FROM EMPLOYEES;

JOB_ID--------------------SA_MANSA_REPSA_REPSA_REPSH_CLERKSH_CLERK

Display All Rows

SQL>SELECT DISTINCT JOB_ID 2 FROM EMPLOYEES;

JOB_ID--------------------AC_ACCOUNTAC_MGRAD_ASSTAD_PRESAD_VPFI_ACCOUNTFI_MGRHR_REP

SQL>SELECT DISTINCT JOB_ID 2 FROM EMPLOYEES;

JOB_ID--------------------AC_ACCOUNTAC_MGRAD_ASSTAD_PRESAD_VPFI_ACCOUNTFI_MGRHR_REP

Display Unique Rows

Duplicate Rows

Limiting Selected Rows

Comparison and Logical Operations

Logical comparison operators= > >= < <=

SQL comparison operators– BETWEEN ... AND– IN (list)– LIKE– IS NULL

Logical operators– AND– OR – NOT

The WHERE Clause

SELECT first_name,last_name,job_idFROM employeesWHERE first_name = 'John‘;

SELECT first_name,last_name,job_idFROM employeesWHERE first_name = 'John‘;

FIRST_NAME LAST_NAME JOB_ID--------------- ------------------------------ ----------------John Chen FI_ACCOUNTJohn Seo ST_CLERKJohn Russell SA_MAN

FIRST_NAME LAST_NAME JOB_ID--------------- ------------------------------ ----------------John Chen FI_ACCOUNTJohn Seo ST_CLERKJohn Russell SA_MAN

Negating Expressions

Logical Operators– != <> ^=

SQL Operator– NOT BETWEEN ... AND ...– NOT IN– NOT LIKE– IS NOT NULL

The ORDER BY Clause

Exercise 2

Installing the Human Resources (HR) Schema 列出薪資超過 10000 之員工姓名 , 受雇日期 , 部門及薪資 列出所有銷售部門的員工編號 , 姓名及薪資 , , 並依受雇日

期做 sorting (descending)

Oracle Date Format

Oracle stores dates in a internal numeric format(Valid date range from January 1, 4712 BC to December 31, 9999 AD)

– Century,year,month,day,hours,minutes,seconds Default date display is DD-MON-RR SYSDATE is a function returning date and time DUAL id a dummy table used to view SYSDATE

RR Date Format

RR Date Format (examples)

SELECT TO_CHAR(TO_DATE(’27-OCT-98’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----1998

SELECT TO_CHAR(TO_DATE(’27-OCT-98’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----1998

SELECT TO_CHAR(TO_DATE(’27-OCT-17’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----2017

SELECT TO_CHAR(TO_DATE(’27-OCT-17’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----2017

YY Date Format (examples)

SELECT TO_CHAR(TO_DATE(’27-OCT-98’, ’DD-MON-YY’) ,’YYYY’) "Year"FROM DUAL;

Year----2098

SELECT TO_CHAR(TO_DATE(’27-OCT-98’, ’DD-MON-YY’) ,’YYYY’) "Year"FROM DUAL;

Year----2098

SELECT TO_CHAR(TO_DATE(’27-OCT-17’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----2017

SELECT TO_CHAR(TO_DATE(’27-OCT-17’, ’DD-MON-RR’) ,’YYYY’) "Year"FROM DUAL;

Year----2017

Display the current date

SQL> SELECT SYSDATE FROM DUAL;

SYSDATE----------------11-OCT-03

SQL> SELECT SYSDATE FROM DUAL;

SYSDATE----------------11-OCT-03

SQL> SELECT TO_CHAR(SYSDATE,’YYYY-MM-DD HH24:MI:SS’) FROM DUAL;

TODAY--------------------------------------2003-10-11 23:07:01

SQL> SELECT TO_CHAR(SYSDATE,’YYYY-MM-DD HH24:MI:SS’) FROM DUAL;

TODAY--------------------------------------2003-10-11 23:07:01

Date Function

MONTHS_BETWEEN(date1,date2) ADD_MONTHS(date,n) NEXT_DAY(date,’char’) LAST_DAY(date) ROUND(date,’fmt’) TRUNC(date,’fmt’)

Exercise 3

列出年資超過 3 年的員工姓名 , 薪資 , 受雇日期

Displaying Data from Multiple Tables

What is a join ?

A Join is used to query data from more than one table

Rows are joined using common values, typically primary and foreign key values

Join methods– Equijoin– Non-equijoin– Outer Join– Self Join

Simple Join Query : Syntax

Write the join condition in the WHERE clause Column names must be prefixed with the table name

when the same column name appears in more than one table

Precede each column name with the table name for clarity

SELECT table1.column,table.columnFROM table1,table2WHERE table1.column1=table2.column2;

SELECT table1.column,table.columnFROM table1,table2WHERE table1.column1=table2.column2;

Cartesian Product

A Cartesian product is formed when– A join condition is omitted – A join condition is invalid– All rows in the first table are joined to all rows in the second

table

To avoid a Cartesian product ,always include a valid join condition in a where clause

Equijoin

SELECT last_name, job_id, departments.department_id, department_nameFROM employees , departments WHERE employees.department_id = departments.department_id

SELECT last_name, job_id, departments.department_id, department_nameFROM employees , departments WHERE employees.department_id = departments.department_id

Table Aliases

SELECT e.last_name,e.job_id, d.department_id, d.department_nameFROM employees e, departments dWHERE e.department_id = d.department_id

SELECT e.last_name,e.job_id, d.department_id, d.department_nameFROM employees e, departments dWHERE e.department_id = d.department_id

Non-Equijoin

SELECT e.ename,e.sal,s.grade,s.losal,s.hisalFROM emp e,salgrade sWHERE e.sal BETWEEN s.losal AND s.hisal;

SELECT e.ename,e.sal,s.grade,s.losal,s.hisalFROM emp e,salgrade sWHERE e.sal BETWEEN s.losal AND s.hisal;

Outer Join

Employees Departments

SQL

Outer Join

SELECT e.first_name,d.department_name,d.department_idFROM departments d,employees eWHERE d.department_id=e.department_id(+)

SELECT e.first_name,d.department_name,d.department_idFROM departments d,employees eWHERE d.department_id=e.department_id(+)

SELECT e.first_name,d.department_name,d.department_idFROM departments d left outer join employees eON d.department_id=e.department_id

SELECT e.first_name,d.department_name,d.department_idFROM departments d left outer join employees eON d.department_id=e.department_id

Standard SQL

Oracle SQL

Self Join

Employees(worker) Employees(manager)

SQL

Self Join

SELECT w.last_name worker , m.last_name managerFROM employees w, employees mWHERE w.manager_id = m.employee_idAND w.last_name LIKE 'R%'

SELECT w.last_name worker , m.last_name managerFROM employees w, employees mWHERE w.manager_id = m.employee_idAND w.last_name LIKE 'R%'

Group Functions

Group function operate on sets of rows to give on result per group

Group function appear in both SELECT lists and HAVING clauses

The GROUP by clause in the SELECT statement divides rows into smaller groups

The HAVING clause restricts result groups

Group Functions

AVG COUNT MAX MIN STDDEV SUM VARIANCE

GROUP BY and HAVING in the SELECT statement

Group Functions (example)

SELECT count(*) FROM employees

SELECT count(*) FROM employees

Group Function (example)

SELECT job_id,SUM(SALARY),AVG(SALARY)FROM employeesGROUP BY job_idHAVING SUM(salary) > 20000ORDER BY SUM(salary)

SELECT job_id,SUM(SALARY),AVG(SALARY)FROM employeesGROUP BY job_idHAVING SUM(salary) > 20000ORDER BY SUM(salary)

Subquery

Subquery is a SELECT statement embedded in a clause of another SQL statement

SELECT ...

FROM ...

WHERE

SELECT ...

FROM ...

WHERE (SELECT ... FROM ... WHERE

MainQuery

Subquery

Subquery (example)

SELECT last_name,email,job_idFROM employeesWHERE department_id IN(SELECT department_id FROM departments WHERE location_id=1700)AND hire_date < '01-JAN-1994'

SELECT last_name,email,job_idFROM employeesWHERE department_id IN(SELECT department_id FROM departments WHERE location_id=1700)AND hire_date < '01-JAN-1994'

SQL Convention

SELECT DISTINCTfn.dept_id dept_id,fcoam.dp_acc_id acc_id,fn.cat,fn.sub_cat,fn.amount

FROM FET_ABM_FA_NBV fn,FET_ABM_FA_DP_RATE_MAP fdr,FET_ABM_FA_COC_ACC_MAP fcoam

WHERE fn.cat = fdr.catAND fn.sub_cat = fdr.sub_catAND fn.cat = fcoam.catAND fn.sub_cat || '-NON NETWORK' = fcoam.sub_cat AND fdr.cat_noNOT IN (1,2,3,4);

SELECT DISTINCTfn.dept_id dept_id,fcoam.dp_acc_id acc_id,fn.cat,fn.sub_cat,fn.amount

FROM FET_ABM_FA_NBV fn,FET_ABM_FA_DP_RATE_MAP fdr,FET_ABM_FA_COC_ACC_MAP fcoam

WHERE fn.cat = fdr.catAND fn.sub_cat = fdr.sub_catAND fn.cat = fcoam.catAND fn.sub_cat || '-NON NETWORK' = fcoam.sub_cat AND fdr.cat_noNOT IN (1,2,3,4);

Table name alias

UpperCase & Left Alignment

Exercise 4

由於 Chen (Last Name) 表現優異 , 董事長決定親自表揚 , 請找出他的工作地點 (City)

在銷售 (Sales) 部門 , 每月員工薪資支出是多少 ( 請列出部門名稱及薪資支出 )

請用計算薪資大於全公司平均薪資的員工數 請列出平均薪資大於全公司平均薪資的部門

( 列出部門名稱）

DAY 2

ERD

Data Models

Model of systemin client’s mind

Entity model

Table model of entity model

Database Server

Table on disk

Create Table Model

Step1:Map Entities to Tables Step2:Map the Attributes to Columns Step3:Map the Unique Identifiers to Primary Keys Step4:Map Relationships to Foreign Keys

Table Instance Chart

Column Name Data Type Key Type Fk Table Null

department_id Number(4) PK1 N

department_name Varchar2(30) N

manager_id Number(6) FK1 employees.emp_id

Y

location_id Number(4) FK2 location.location_id

Y

DEPARTMENTS Table

Creating Tables

Database objects

Object Description

Table Basic unit of storage composed of rows and columns

View Logically represents subsets of data from one or more tables

Sequence Generate primary key values

Index Improves the performance of some queries

Synonym Alternate name for an object

Program Unit Procedure, function or package of SQL and PL/SQL statement

Datatypes

Datatype Description

VARCHAR2(size) Variable length character value ,max 4000 bytes

CHAR(size) Fixed length character value, max 2000 bytes

NUMBER(precision,scale)

Number Values

DATE Date & Time values, January 1, 4712 BC to

December 31, 9999 AD.

CLOB Character large object, max 4Gb

BLOB Binary large object, max 4Gb

Number Type

Data Integrity Constraints

Constraint Description

NOT NULL Specifies that this may not contain a null value

UNIQUE Specifies a column or combination of columns whose values must be unique for all rows in the table.

PRIMARY KEY Uniquely identifies each row of the table.

FOREIGN KEY Establishes and enforces a foreign key relationship

between the column and a column of the referenced

table.

CHECK Specifies a condition that must be true.

Creating Table (example)

Creating Table (example)

Create Table (example)

Data Dictionary ( I )

Create when database is created Updated and maintained by the Oracle Server Information stored in the data dictionary

– Names of Oracle Server user– Privileges granted to users– Database object names– Table constraints– Auditing Information

Data Dictionary (II)

Four classes of views (prefixes)– USER Objects owned by user– ALL Objects user has access rights– DBA All database objects– V$ Performance Information

Checking Constraint on a Table

SELECT CONSTRAINT_NAME,COLUMN_NAME,POSITIONFROM USER_CONS_COLUMNSWHERE TABLE_NAME =‘DEPARTMENTS'ORDER BY CONSTRAINT_NAME,POSITION

SELECT CONSTRAINT_NAME,COLUMN_NAME,POSITIONFROM USER_CONS_COLUMNSWHERE TABLE_NAME =‘DEPARTMENTS'ORDER BY CONSTRAINT_NAME,POSITION

Manipulating Data

DML & Transaction Control

Command Description

INSERT Add new rows to the table

UPDATE Modify existing rows in the table

DELETE Remove existing rows in the table

COMMIT Make all pending changes permanent

SAVEPOINT Allows a rollback to that savepoint maker

ROLLBACK Discards all pending data changes

Adding a New Row to a Table

INSERT INTO DEPARTMENTS (department_id,department_name,manager_id,location_id)VALUES (271,'Outsoucing',NULL,1700);

INSERT INTO DEPARTMENTS (department_id,department_name,manager_id,location_id)VALUES (271,'Outsoucing',NULL,1700);

INSERT INTO table [ ( column [ , column ...] ) ]VALUES ( value [, value ....] );

INSERT INTO table [ ( column [ , column ...] ) ]VALUES ( value [, value ....] );

Example

Syntax

Copy Rows from Another Table

Write INSERT command with subquery Do not use VALUES clause Match the number of columns in the INSERT

clause to those in subquery

INSERT INTO JOB_HISTORY (employee_id,start_date,end_date,job_id,department_id)SELECT employee_id,hire_date,SYSDATE,job_id,department_idFROM employeesWHERE job_id=‘SH_CLERK’

INSERT INTO JOB_HISTORY (employee_id,start_date,end_date,job_id,department_id)SELECT employee_id,hire_date,SYSDATE,job_id,department_idFROM employeesWHERE job_id=‘SH_CLERK’

Update Rows in a Tables

UPDATE employeesSET salary = salary * 1.05WHERE job_id ='SA_REP'

UPDATE employeesSET salary = salary * 1.05WHERE job_id ='SA_REP'

Example

UPDATE tableSET column = value , [column = value ][ WHERE condition ] ;

UPDATE tableSET column = value , [column = value ][ WHERE condition ] ;

Syntax

Deleting Rows from a Table

DELETE employeesWHERE job_id like ‘IT%’

DELETE employeesWHERE job_id like ‘IT%’

Example

DELETE table[ WHERE condition ] ;

DELETE table[ WHERE condition ] ;

Syntax

Data Consistency (Transaction)

Atomicity ( 不可分割性 ) Durability ( 持續性 )

COMMIT and ROLLBACK

Ensure data consistency Preview data changes before making changes

permanent Group logically related operations

State of the Data Before COMMIT or ROLLBACK

The previous state of the data can be recovered The current user can review the results of the DML

operations by using the SELECT statement Other users cannot view the results of the DML

statements by the current user The affected rows are locked; other users cannot

change the data within the affected rows

State of the Data After COMMIT

The previous data is permanently lost All users can view the results Locks on the affected rows are released

Committing Data (example)

SQL> INSERT INTO DEPARTMENTS 2 (department_id,department_name,manager_id,location_id) 3 VALUES (271,'Outsoucing',NULL,1700);

1 row created.

SQL> COMMIT;

Commit complete.

SQL> INSERT INTO DEPARTMENTS 2 (department_id,department_name,manager_id,location_id) 3 VALUES (271,'Outsoucing',NULL,1700);

1 row created.

SQL> COMMIT;

Commit complete.

State of the Data After ROLLBACK

Data change are undone Previous state of the data restored Locks on the affected rows are released

Rollback Data (example)

SQL> DELETE JOB_HISTORY;

10 rows deleted.

SQL> SELECT COUNT(*) FROM JOB_HISTORY;

COUNT(*)---------- 0

SQL> ROLLBACK;

Rollback complete.

SQL> SELECT COUNT(*) FROM JOB_HISTORY;

COUNT(*)---------- 10

SQL> DELETE JOB_HISTORY;

10 rows deleted.

SQL> SELECT COUNT(*) FROM JOB_HISTORY;

COUNT(*)---------- 0

SQL> ROLLBACK;

Rollback complete.

SQL> SELECT COUNT(*) FROM JOB_HISTORY;

COUNT(*)---------- 10

Creating Sequences

CREATE SEQUENCE sequence_name [INCREMENT BY n ] [START WITH n ] [ {MAXVALUE n | NOMAXVALUE } ] [ {MINVALUE n | NOMMINVALUE } ] [ { CYCLE | NOCYCLE } ] [ { CACHE n | NOCACHE } ]

CREATE SEQUENCE sequence_name [INCREMENT BY n ] [START WITH n ] [ {MAXVALUE n | NOMAXVALUE } ] [ {MINVALUE n | NOMMINVALUE } ] [ { CYCLE | NOCYCLE } ] [ { CACHE n | NOCACHE } ]

Syntax

Creating Sequences

CREATE SEQUENCE S1 INCREMENT BY 2START WITH 5MINVALUE 1MAXVALUE 10NOCACHECYCLE

CREATE SEQUENCE S1 INCREMENT BY 2START WITH 5MINVALUE 1MAXVALUE 10NOCACHECYCLE

Example

5 8 1 4 7 10 1 4 7 10

What Is a View ?

Advantages of Views

Restrict database access Simplify queries Present the data in a different perspective from that

of the base table Isolate applications from changes in definitions of

base tables Provide groups of users access to data according to

their particular criteria.

Creating a View

The subquery can contain complex SELECT syntax The subquery cannot an ORDER BY clause

CREATE VIEW view_name[ ( alias , [ alias ]...)]AS subquery[WITH CHECK OPTION [CONSTRAINT constraint]][WITH READ ONLY]

CREATE VIEW view_name[ ( alias , [ alias ]...)]AS subquery[WITH CHECK OPTION [CONSTRAINT constraint]][WITH READ ONLY]

Syntax

Creating a View (example)

Create the STAFF_60_V,which contain employee number, last name ,job ,manager’s employee number and department id for the employees in department 60

CREATE VIEW STAFF_60_V(employee_id,last_name,job_id,manager_id,department_id)ASSELECT employee_id,last_name,job_id,manager_id,department_idFROM employeesWHERE department_id= 60

CREATE VIEW STAFF_60_V(employee_id,last_name,job_id,manager_id,department_id)ASSELECT employee_id,last_name,job_id,manager_id,department_idFROM employeesWHERE department_id= 60

Creating a Complex View (example)

Creating a complex view that contain group function to display values from two tables

CREATE VIEW DEPT_SALARY_VIEWASSELECT d.department_name,SUM(salary) sum_salary ,MIN(SALARY) min_salary,MAX(SALARY) max_salaryFROM EMPLOYEES e,DEPARTMENTS dWHERE e.department_id = d.department_idGROUP BY d.department_name

CREATE VIEW DEPT_SALARY_VIEWASSELECT d.department_name,SUM(salary) sum_salary ,MIN(SALARY) min_salary,MAX(SALARY) max_salaryFROM EMPLOYEES e,DEPARTMENTS dWHERE e.department_id = d.department_idGROUP BY d.department_name

Exercise 5

Create View 列出員工姓名及主管姓名 (last name & first name)

由於業務部門績效良好 , 董事長決定全部加薪 10%, 請更改他們的薪資 , 並列出薪資超出該職務（ job_id) 上限的人員

公司決定自即日起將 IT 工作外包 , 請將 IT 人員自 employees Table 中移除，並將相關資料放至 job_history

What Is a Index ?

Database Object Each index is composed of column values and

pointers (or ROWID) Indexes is maintained and used by RDBMS

Index Type

By constraint– Unique– Non-unique

By constitution– Single Column– Concatenated or Composite

How are Indexes Created ?

Automatically– A unique index are created when you define PRIMARY KE

Y or UNIQUE KEY constraint in a table defination

Manually– CREATE INDEX command

Creating and Index

CREATE [UNIQUE ] INDEX index_name ON table (column [,column]...)

CREATE [UNIQUE ] INDEX index_name ON table (column [,column]...)

Syntax

CREATE UNIQUE INDEX job_id_pk ON jobs (job_id) ;

CREATE UNIQUE INDEX job_id_pk ON jobs (job_id) ;

Example

Guideline to Create an Index

The columns are used frequently in WHERE clause or in join condition

The column contain a wide range of values The column contain a large number of null value

Confirming Indexes

USER_INDEXES USER_IND_COLUMNS

DAY 3

PL/SQL

PL/SQL Block Structure

DECLARE (Optional)– Variables,constants,cursors,user-defined exception

BEGIN (Mandatory)– SQL Statements– PL/SQL Control statement

EXCEPTION (Optional)– Action to perform when errors occurs

END; (Mandatory)

Example PL/SQL Block

DECLAREEmp_name VARCHAR2(10);Emp_number INTEGER;

Empno_out_of_range EXCEPTION;BEGIN

Emp_number := 10001;IF Emp_number > 9999 OR Emp_number < 1000 THENRAISE Empno_out_of_range;ELSESELECT Ename INTO Emp_name FROM Emp_tabWHERE Empno = Emp_number;DBMS_OUTPUT.PUT_LINE('Employee name is' || Emp_name);END IF;

EXCEPTIONWHEN Empno_out_of_range THENDBMS_OUTPUT.PUT_LINE('Employee number' || Emp_number ||'is out of range.');

END;

Block Types

Anonymous Procedure

[DECLARE]

BEGIN

-- Statement[EXCEPTION]

END;

[DECLARE]

BEGIN

-- Statement[EXCEPTION]

END;

PROCEDURE nameIS

BEGIN

-- Statement[EXCEPTION]

END;

PROCEDURE nameIS

BEGIN

-- Statement[EXCEPTION]

END;

Function

FUNCTION nameRETURN datatypeIS

BEGIN

-- StatementRETURN value;[EXCEPTION]

END;

FUNCTION nameRETURN datatypeIS

BEGIN

-- StatementRETURN value;[EXCEPTION]

END;

Program Constructs

Stored Procedure and Function (Package) Application Procedure and Function (Package) Database Trigger Application Trigger (Form ,Report) Anonymous Block

Declare Variables

PL/SQL variables– Scalar– Composite– Reference (Pointer)– LOB (Large Objects)

Built-in Datatypes Quick Ref.

Declaring PL/SQL Variable

identifier [CONSTANT] datatype [NOT NULL] [:= | DEFAULT expr ];

identifier [CONSTANT] datatype [NOT NULL] [:= | DEFAULT expr ];

Declarev_adjust_amount NUMBER NOT NULL:= 0;v_nbv_amount NUMBER := 0;v_dis_nbv_amount NUMBER := 0;

Declarev_adjust_amount NUMBER NOT NULL:= 0;v_nbv_amount NUMBER := 0;v_dis_nbv_amount NUMBER := 0;

Syntax

Example

Declaring Variables with the %TYPE Attribute

Example

…DECLAREv_ename emp.ename%TYPE;v_balance NUMBER(7,2);…

…DECLAREv_ename emp.ename%TYPE;v_balance NUMBER(7,2);…

Base Scalar Datatypes

VARCHAR2(maximun_length) NUMBER[(precision,scale)] DATE CHAR(maximun_length) ………

Code Naming Convention

Identifier Naming Conversion Example

Variable v_name v_sal

Constant c_name c_company_name

Cursor name_cursor emp_cursor

Exception e_name e_too_many

Table type name_table_type amount_table_type

Table name_table order_total_table

Record Type name_record_type emp_record_type

Record name_record customer_record

SELECT statement in PL/SQL

SELECT select_listINTO { variable_name [,variable_name]....

| record_name }FROM tableWHERE condition;

SELECT select_listINTO { variable_name [,variable_name]....

| record_name }FROM tableWHERE condition;

Retrieve data from the database with SELECT

Syntax

SELECT statement in PL/SQL

INTO clause Queries Must Return One and Only One Row

– NO_DATA_FOUND– TOO_MANY_ROWS

Simple PL/SQL Block

DECLAREv_deptno NUMBER(2);v_loc VARCHAR2(15);

BEGINSELECT deptno

,locINTO v_deptno

,v_locFROM deptWHERE dname='SALES';

DBMS_OUTPUT.PUT_LINE(TO_CHAR(v_deptno)); DBMS_OUTPUT.PUT_LINE(v_loc);END;

DECLAREv_deptno NUMBER(2);v_loc VARCHAR2(15);

BEGINSELECT deptno

,locINTO v_deptno

,v_locFROM deptWHERE dname='SALES';

DBMS_OUTPUT.PUT_LINE(TO_CHAR(v_deptno)); DBMS_OUTPUT.PUT_LINE(v_loc);END;

Exercise 6

1. Create a PL/SQL block that selects the maximum department number in the DEPT table and print the results to the screen.

2. Modified the PL/SQL block you created in previous exercise to insert a new department into DEPT table

– add 10 to the maxinum department number– Use SQL*Plus substitution variable for the department name– Leave the location null

Determining Variable Scope

DECLARE v_sal NUMBER(7,2) := 6000; v_comm NUMBER(7,2) := v_sal * 0.2; v_message VARCHAR2(255) := 'eligible for commission';BEGIN DECLARE v_sal NUMBER(7,2) := 50000; v_comm NUMBER(7,2) := 0; v_total_comp NUMBER(7,2) := v_sal + v_comm; BEGIN v_message := 'CLERK not' || v_message; END; v_message := 'SALESMAN' || v_message;END;

DECLARE v_sal NUMBER(7,2) := 6000; v_comm NUMBER(7,2) := v_sal * 0.2; v_message VARCHAR2(255) := 'eligible for commission';BEGIN DECLARE v_sal NUMBER(7,2) := 50000; v_comm NUMBER(7,2) := 0; v_total_comp NUMBER(7,2) := v_sal + v_comm; BEGIN v_message := 'CLERK not' || v_message; END; v_message := 'SALESMAN' || v_message;END;

Commenting Code

Prefix single-line comments with two dash(--) Place multi-line comments between the symbols

/* and */

... v_sal NUMBER(7,2);BEGIN /* Compute the annual salary based on the monthly salary input from the user */ v_sal := &p_monthly_sal * 12;END; -- This is the end of the block

... v_sal NUMBER(7,2);BEGIN /* Compute the annual salary based on the monthly salary input from the user */ v_sal := &p_monthly_sal * 12;END; -- This is the end of the block

Writing Control Structures

IF statement LOOP GOTO

IF Statement

Conditional IF statements– IF-THEN-END IF– IF-THEN-ELSE-END IF– IF-THEN-ELSIF-END IF

Simple IF Statement

...IF v_ename = 'MILLER' THENTHEN v_job := 'SALESMAN'; v_new_comn := sal * 0.2;ELSIF v_ename = 'JONES' THEN v_job := 'MANAGER'; v_new_comn := sal * 0.2;ELSE ...........END IF;

...IF v_ename = 'MILLER' THENTHEN v_job := 'SALESMAN'; v_new_comn := sal * 0.2;ELSIF v_ename = 'JONES' THEN v_job := 'MANAGER'; v_new_comn := sal * 0.2;ELSE ...........END IF;

Basic Loop

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1;BEGIN LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; EXIT WHEN v_counter > 10; END LOOP;END;

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1;BEGIN LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; EXIT WHEN v_counter > 10; END LOOP;END;

FOR loop

BEGIN FOR i IN 1..10 LOOP INSERT INTO item(ordid,itemid) VALUES (i,v_counter); END LOOP;END;

BEGIN FOR i IN 1..10 LOOP INSERT INTO item(ordid,itemid) VALUES (i,v_counter); END LOOP;END;

Do not declare the counter,it is declared implicitly

WHILE Loop

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1;BEGIN

WHILE v_counter <= 10 LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; END LOOP;END;

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1;BEGIN

WHILE v_counter <= 10 LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; END LOOP;END; exit

Nested Loop and Labels

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1; v_dummy NUMBER;BEGIN LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; IF v_counter > 10 THEN GOTO end_loop; END IF; END LOOP;<<end_loop>>v_dummy := 1;END;

DECLARE v_ordid item.ordid%TYPE := 601; v_counter NUMBER(2) := 1; v_dummy NUMBER;BEGIN LOOP INSERT INTO item(ordid,itemid) VALUES (v_ordid,v_counter); v_counter := v_counter + 1; IF v_counter > 10 THEN GOTO end_loop; END IF; END LOOP;<<end_loop>>v_dummy := 1;END;

Practice 7

CREATE TABLE MESSAGES(RESULT VARCHAR2(100));

– Insert the number 1 to 10 ,excluding 6 and 8

– Select from the MESSAGES table to verify that your PL/SQL block work

Add a new column called STARS of datatype VARCHAR2 and length 20 ,to the EMP table ,Update STARS column as the following result

Composite Datatypes

PL/SQL RECORDS PL/SQL TABLES

PL/SQL Record

DECLARETYPE emp_record_type IS RECORD(ename VARCHAR2(10),

job VARCHAR2(9), sal NUMBER(7,2));

emp_record emp_record_type;BEGINEND;

DECLARETYPE emp_record_type IS RECORD(ename VARCHAR2(10),

job VARCHAR2(9), sal NUMBER(7,2));

emp_record emp_record_type;BEGINEND;

The %ROWTYPE Attribute

DECLARE emp_record emp%ROWTYPE;BEGIN ….END;

DECLARE emp_record emp%ROWTYPE;BEGIN ….END;

PL/SQL Tables

TYPE ename_table_type IS TABLE of emp.ename%TYPE INDEX BY BINARY_INTEGER;

ename_table ename_table_type;

TYPE ename_table_type IS TABLE of emp.ename%TYPE INDEX BY BINARY_INTEGER;

ename_table ename_table_type;

Writing Explicit Cursor

About Cursors

– Implicit Cursors :Declared for all DML and PL/SQL SELECT statement

– Explicit Cursors:Declared and named by the programmer

Every SQL Statement executed by the Oracle Server has an indifidual cursor associated with it

Explicit Cursor Function

7369 SMITH CLERK7499 ALLEN SALESMAN7521 WARD SALESMAN7566 JONES MANAGER7654 MARTIN SALESMAN7698 BLAKE MANAGER

cursor Current row

Controlling Explicit Cursor

DECLARE FETCH CLOSEOPEN EMPTY?

NO

YES

Explicit Cursor example

DECLARE CURSOR emp_cur IS SELECT ename,job FROM EMP; emp_record emp_cur%ROWTYPE;BEGIN OPEN emp_cur; LOOP FETCH emp_cur INTO emp_record; EXIT WHEN emp_cur%NOTFOUND; END LOOP; CLOSE emp_cur;END;

DECLARE CURSOR emp_cur IS SELECT ename,job FROM EMP; emp_record emp_cur%ROWTYPE;BEGIN OPEN emp_cur; LOOP FETCH emp_cur INTO emp_record; EXIT WHEN emp_cur%NOTFOUND; END LOOP; CLOSE emp_cur;END;

Explicit Cursor Attribute

Attribute Type Description

%ISOPEN Boolean Evaluates to TRUE if the cursor is open

%NOTFOUND Boolean Evaluates to TRUE if the most recent fetch does not return a row

%FOUND Boolean Evaluates to TRUE if the most recent fetch returns a row

%ROWCOUNT Number Evaluates to the total number of rows returned so far

Cursor FOR Loops

DECLARE CURSOR emp_cur IS SELECT ename,job FROM EMP;BEGIN FOR emp_record IN emp_cur LOOP -- implicit open and implicit fetch occur IF emp_record.deptno = 30 THEN ......... END IF; END LOOP; -- implicit close occursEND;

DECLARE CURSOR emp_cur IS SELECT ename,job FROM EMP;BEGIN FOR emp_record IN emp_cur LOOP -- implicit open and implicit fetch occur IF emp_record.deptno = 30 THEN ......... END IF; END LOOP; -- implicit close occursEND;

Cursors with Parameters

DECLARE CURSOR emp_cursor (p_deptno NUMBER,p_job VARCHAR2) IS SELECT empno,ename FROM emp WHERE deptno = p_deptno AND job = p_job;BEGIN OPEN emp_cursor (10,'CLERK')......

DECLARE CURSOR emp_cursor (p_deptno NUMBER,p_job VARCHAR2) IS SELECT empno,ename FROM emp WHERE deptno = p_deptno AND job = p_job;BEGIN OPEN emp_cursor (10,'CLERK')......

Pass the department number and job title to the WHERE clause do not give them sizes

Cursor with Parameters

DECLARE CURSOR emp_cursor (p_deptno NUMBER,p_job VARCHAR2) IS SELECT empno,ename FROM emp WHERE deptno = p_deptno AND job = p_job;BEGIN FOR emp_record IN emp_cursor(10,'CLERK') LOOP ..... END LOOP;

DECLARE CURSOR emp_cursor (p_deptno NUMBER,p_job VARCHAR2) IS SELECT empno,ename FROM emp WHERE deptno = p_deptno AND job = p_job;BEGIN FOR emp_record IN emp_cursor(10,'CLERK') LOOP ..... END LOOP;

You can pass parameters to the cursor used in a cursor FOR loop

The FOR UPDATE Clause

DECLARE CURSOR emp_cursor IS SELECT empno,ename FROM emp WHERE deptno = 30 FOR UPDATE [ OF sal ] NOWAIT;

DECLARE CURSOR emp_cursor IS SELECT empno,ename FROM emp WHERE deptno = 30 FOR UPDATE [ OF sal ] NOWAIT;

Optional

The FOR UPDATE Clause

Lock the affected rows when the cursor is opened You should not commit across fetched from a explicit curs

or if FOR UPDATE is used(because the Oracle Server releases locks at the end fo the transaction)

FOR UPDATE clause is the last clause in a select statement

The WHERE CURRENT OF Clause

Use cursors to update or delete the current row Include the FOR UPDATE clause in the cursor query to lock the rows

first Use the WHERE CURRENT OF clause to reference the current row

from an explicit cursor

Syntax:

WHERE CURRENT OF cursor;WHERE CURRENT OF cursor;

The WHERE CURRENT OF Clause (example)

DECLARE CURSOR sal_cursor IS SELECT sal FROM emp WHERE deptno = 30 FOR UPDATE OF sal NOWAIT;BEGIN FOR emp_record IN sal_cursor LOOP

UPDATE empSET sal = sal * 1.10WHERE CURRENT OF sal_cursor;

END LOOP;END;

DECLARE CURSOR sal_cursor IS SELECT sal FROM emp WHERE deptno = 30 FOR UPDATE OF sal NOWAIT;BEGIN FOR emp_record IN sal_cursor LOOP

UPDATE empSET sal = sal * 1.10WHERE CURRENT OF sal_cursor;

END LOOP;END;

Summary (Cursor)

Cursor type:– Implicit cursors:Used for all DML statements and single-row querie

s– Explicit cursors:Used for queries of zero,one,or more rows

You can manipulate explicit cursors You can evaluate the cursor status by using cursor attributes You can use cursor FOR loops

Handling Exceptions

Handling Exceptions with PL/SQL

What is an exception– In PL/SQL, a warning or error condition is called an exception.

How is it raised?– An Oracle error occurs– You raise it explicitly

How do you handle it?– Trap it with a handle it– Propagate it to the calling environment

Handling Exception

Trap the exception Propagate the exception

DECLARE

BEGIN

EXCEPTION

END;

exception is raised

exception is trapped

DECLARE

BEGIN

EXCEPTION

END;

exception is raised

exception is not trapped

Excepiton propagates to calling environment

Exception Types

Predefined Oracle Server Non-predefined Oracle Server User-defined

Implicitly raised

Explicitly raised

Trapping Exceptions Guildlines

WHEN OTHERS is the last cluase EXCEPTION keyword start exception handling section Serveral exception handlers are allowed Only one handler is processed before leaving the block

Predefined Exception (example)

BEGIN EXCEPTION WHEN NO_DATA_FOUND THEN statement1; statement2; WHEN TOO_MANY_ROWS THEN statement1; statement2; WHEN OTHERS THEN statement1; statement2; END;

BEGIN EXCEPTION WHEN NO_DATA_FOUND THEN statement1; statement2; WHEN TOO_MANY_ROWS THEN statement1; statement2; WHEN OTHERS THEN statement1; statement2; END;

Predefined Oracle Server Errors

Using SQLCODE & SQLERRM

User-Defined Exception

How Exception Propagate

How Exception Propagate

How Exception Propagate

Practice 8

Write a PL/SQL block to select the name of the employee with a given salary,insert the result in MESSAGES table

RESULT--------------------------------------------------------------------------------SMITH -800More than one employee with a salary of 3000No employee with a salary 6000

Stored Procedures & Functions

Create Stored Procedure (example)

CREATE OR REPLACE PROCEDURE raise_salary (emp_id INTEGER, amount NUMBER) IScurrent_salary NUMBER;salary_missing EXCEPTION;

BEGINSELECT sal INTO current_salary FROM empWHERE empno = emp_id;IF current_salary IS NULL THENRAISE salary_missing;ELSEUPDATE emp SET sal = sal + amountWHERE empno = emp_id;END IF;

EXCEPTIONWHEN NO_DATA_FOUND THENINSERT INTO emp_audit VALUES (emp_id, 'No such number');WHEN salary_missing THENINSERT INTO emp_audit VALUES (emp_id, 'Salary is null');

END raise_salary;

CREATE OR REPLACE PROCEDURE raise_salary (emp_id INTEGER, amount NUMBER) IScurrent_salary NUMBER;salary_missing EXCEPTION;

BEGINSELECT sal INTO current_salary FROM empWHERE empno = emp_id;IF current_salary IS NULL THENRAISE salary_missing;ELSEUPDATE emp SET sal = sal + amountWHERE empno = emp_id;END IF;

EXCEPTIONWHEN NO_DATA_FOUND THENINSERT INTO emp_audit VALUES (emp_id, 'No such number');WHEN salary_missing THENINSERT INTO emp_audit VALUES (emp_id, 'Salary is null');

END raise_salary;

Execute Stored Procedure

EXEC RAISE_SALARY(7900,300)EXEC RAISE_SALARY(7900,300)

BEGIN RAISE_SALARY(7900,300)END;

BEGIN RAISE_SALARY(7900,300)END;

BEGIN RAISE_SALARY (emp_id => 7900 amount => 300 );END;

BEGIN RAISE_SALARY (emp_id => 7900 amount => 300 );END;

Create Stored Function (example)

CREATE OR REPLACE FUNCTION emp_sal_query (i_empno NUMBER) RETURN NUMBERIS v_sal NUMBER;BEGIN

SELECT sal INTO v_salFROM empWHERE empno = i_empno;

RETURN v_sal;EXCEPTION

WHEN NO_DATA_FOUND THENRETURN NULL;

END emp_sal_query;

CREATE OR REPLACE FUNCTION emp_sal_query (i_empno NUMBER) RETURN NUMBERIS v_sal NUMBER;BEGIN

SELECT sal INTO v_salFROM empWHERE empno = i_empno;

RETURN v_sal;EXCEPTION

WHEN NO_DATA_FOUND THENRETURN NULL;

END emp_sal_query;

Execute Stored Function

SELECT emp_sal_query(7369) FROM dual;SELECT emp_sal_query(7369) FROM dual;

SELECT emp_sal_query(empno),ename FROM emp;SELECT emp_sal_query(empno),ename FROM emp;

DECLARE

v_sal NUMBER;

BEGIN

v_sal := emp_sal_query(7369) ;

DBMS_OUTPUT.PUT_LINE(TO_CHAR(v_sal));

END;

DECLARE

v_sal NUMBER;

BEGIN

v_sal := emp_sal_query(7369) ;

DBMS_OUTPUT.PUT_LINE(TO_CHAR(v_sal));

END;

Practice 9

SQL*Loader Overview

Discarded and Rejected Records

SQL*Loader Case Studies

$ORACLE_HOME/rdbms/demo/ulcase*.*

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