Introduction to Databases and Information Management
This domain tests how data is organised in databases and how information is retrieved and presented.
Core concepts
- A database is an organised collection of related data. A table stores data in rows and columns.
- A field is a column (attribute); a record is a row (one entity).
- A primary key uniquely identifies each record and cannot be null or duplicated. A foreign key links to a primary key in another table.
- A DBMS manages storage, retrieval, and security. Queries retrieve data, forms support data entry, and reports present output.
- Relational databases use related tables; flat files keep everything in one table and often repeat data.
Worked example
A Student table has AdmissionNo, Name, Class, and DateOfBirth. Two students can share a name, so Name is not a safe primary key. AdmissionNo is unique and never blank, so it is the correct primary key. The reasoning is uniqueness plus non-nullness: a primary key must identify exactly one record.
Traps that cost marks
- Choosing a name or date of birth as a primary key when duplicates are possible.
- Confusing a field with a record.
- Saying a query permanently stores data; it usually retrieves it.
- Ignoring data validation, which allows inconsistent entries.