GCSE Computing - Databases

GCSE Computing - Databases

1. A database is a set of ordered and related data.

   • It can be easily and quickly edited and searched

2. The Use of a Database System

   • Common places where they use databases
     • Schools
     • Shops
   • It Allows Users to
     • Maintain
       • Add/edit/delete data
     • Create
       • Add tables, define fields and validation
     • Interrogate
       • Run queries to extract information from the database

3. DBMS

   • Database Management System
     • This system separates the data from data handling applications used to maintain and interrogate the databse
   • Concurrent Usage
     • Allows multiple users to access it at the same time
   • Security
     • Ability to allow/restrict data access to users/applications
   • Backup
     • Provides backup solutions to ensure data is not lost in an event of failure
   • Data Integrity
     • Enforcing data integrity by ensuring data is consistent

4. Data Validation

   • Data types
     • These tell the database what format of data to expect
       • Text
       • Integers
       • Decimals
       • Boolean
       • List
   • Data Range
     • Rules can be set up to only allow certain values or ensuring the text starts with a certain characters/symbol and has a particular length
   • Makes sure that only the right data is entered into the database

5. Relational Database

   • It is when that data is separated into individual tables (entities) that are linked by a primary key, which appears in each table
   • The advantage of this is that data redundancy (duplicated) is avoided.
     • Because data is updated in one table it changes automatically in others.
   • Forms
     • Provide a customisable user interface to add/edit and delete data
   • Tables
     • Represents the entity in the database.
     • Fields and primary keys are defined and data is stored in tables
   • Queries
     • Allow data that meets specific criteria to be extracted and displayed
   • Reports
     • Displays the result of queries in a costumised format designed to be printed