OCR AS Computing - Databases

OCR AS Computing - Databases

1. Concepts

   • Entities
     • A category of a real world object about which data is to be recorded
     • Each table in a database
   • Flat file
     • A database consisting of a single file
     • May promote data redundancy
   • Primary key
     • A unique identifier towards every record in a table
   • Secondary key
     • An identifier that is known, but may not be unique, that can identify a specific record
   • Foreign key
     • A primary key from another table in a database that is related to another entity within that database
   • Relational
     • A database that has more than one table, and has foreign keys between them

2. Entity Relationships

   • One-to-many
   • One-to-one
   • Many-to-many

3. Normalisation

   • No data redundancy
   • Correct data consistency
   • Structure of each table is flexible to allow required information to be entered
   • Structure should allow for complex queries

4. Capturing and Managing Data

   • Manual capturing
     • Forms
     • Questionnaires
     • Examinations
     • Cheques
   • Use of EDI (Electronic Data Interchange)
     • Transfers data between one computer system and another
     • Used standard message formatting, documents can be exchanged electronically
   • Use of databases