Mathematics. Session Hyperbola Session - 2 Session Objectives.
Session Objectives # 20
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GCSE Computing#BristolMet Session Objectives# 20 MUST describe a database and discuss the legal implications of storing personal information SHOULD explain the use of logical operators in framing database queries COULD create methods of validating data as it is input. Create a customised user interface to automate functionality such as searching and amending the database
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Session Objectives # 20 . Key Words. Key Words. Field. Record. Data Type. Primary Key. Query. Validation. Database Schema. Database File. - PowerPoint PPT Presentation
Transcript of Session Objectives # 20
GCSE Computing#BristolMet
Session Objectives# 20
MUST describe a database and discuss the legal implications of storing personal information
SHOULD explain the use of logical operators in framing database queries
COULD create methods of validating data as it is input.
Create a customised user interface to automate functionality such as searching and amending the database
GCSE Computing#BristolMet
Key WordsKey Words
Data Type
ValidationQuery
Field Record
Primary Key
Database File
Table
Record
Field
Data Type
Value
This is the main file that holds the entire database. It’s usually saved on a hard drive or network server but can be saved on a portable storage device.
A table is a collection of data about a specific topic, i.e table of student names and addresses There can be many tables in a single database. When these tables are linked together it is known as a relational database.
A group of fields which are related in some way, i.e a student record could be: Surname, Forename, Date of Birth, Tutor Group etc.
Individual data items with their own data type are known as fields. An example is a Date of Birth field (NB its data type will be Date)
Data types are the properties of each field. Each field only has one data type – this aids storage and searching facilities.
A value is each individual data entry, occupying one cell, i.e, for the student record example, it could be just a students’ Surname.
Database Schema
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Data Types TestMr Smith
38 High Street,
Weston – Super – Mare
Somerset
BS23 6AR
(0117) 9236666
1/11/05
Number 1
2
3
4
6
Text
Text
Alpha Numeric – Text or Memo
Hyperlink7 Date/Time
5 Text
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Logical Operators
< <= = > >=<>
Less thanLess than or equal toEqual toMore thanMore than or equal toNot equal to
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Use of Logical Operators
Write the following statements using logical operators
Less than £200
Greater than £300
Equal to or more than £500
Less than or equal to £150
Greater than £225
Everything that is not equal to £250
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Database Interrogation
This is the technical term for searching a database or querying.
TASK: Complete the Customer Enquires tasks on the travel agent database.
EXTENSION: Customer Enquiries 2
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Data Validation
This means to only allow sensible or valid data into the system at the point of entry. There are many methods which can be used to reduce the chance of data entry errors.
Can you think of any??Format check or Input Mask – e.g. 2 letters then 2 numbers – PR15 would be valid.Presence check – checking that the field contains data.Range check – data is between certain numbers or letters, e.g. A–E.Lookup check – only values from a set list can be entered, e.g. M or F.Size check – checking data is more or less than a minimum or maximum number of characters.
