Database Concepts and Management
What the domain covers
Database Concepts and Management tests how data is stored in tables, why keys matter, how relationships work, and how queries/forms/reports are used. Expect definition-plus-application questions rather than heavy SQL.
Core rules
- A database is an organised collection of related data; a DBMS is the software that creates, manages and secures it.
- A table (relation) has fields (columns/attributes) and records (rows/tuples). Each field has a data type and may have validation rules.
- A primary key uniquely identifies each record and cannot be null or duplicated. A foreign key in one table refers to a primary key in another and may repeat; it creates relationships.
- Common relationships: one-to-one, one-to-many, many-to-many. Avoid storing the same fact repeatedly; split repeating groups into separate tables.
- A query retrieves selected fields/records by criteria; a form supports data entry; a report presents formatted output.
Worked example
In a Student table with fields RollNo, Name, Class, Phone, RollNo is the best primary key because it is unique and stable. Name is a poor choice because two students can share a name; Phone may be blank or change. A query for Class 10 students uses the criterion Class = "10".
Traps
- Confusing a field with a record: a row is a record, a column is a field.
- Allowing duplicate or blank values in a primary key.
- Thinking a foreign key must be unique - it often repeats.
- Using a DBMS and a database as synonyms in a definition question.