OCR A Level Computer Science (H446) - Component 1.3.2 - Databases

A database is...

• a structured system for holding records

• a spreadsheet of information

• reliant on good design, as poor structure can cause many problems

• simple and easy to create

An entity is...

• A thing, about which data is stored in the database such as Student

• A property such as Name or Age

An attribute is...

• A thing, about which data is stored in the database such as Student

• A property such as Name or Age

In a hospital system, the relationship between a consultant to a patient would be:

• One-to-One

• One-to-Many

• Many-to-Many

• Many-to-One

In a hospital system, the relationship between a nurse to a ward would be:

• One-to-One

• One-to-Many

• Many-to-Many

• Many-to-One

In a school system, the relationship between teachers and pupils would be:

• One-to-One

• One-to-Many

• Many-to-Many

• Many-to-One

In a school system, the relationship between a teacher to a department would be:

• One-to-One

• One-to-Many

• Many-to-Many

• Many-to-One

A primary key is...

• A unique identifier for each record

• An identifier which can be shared between multiple records

• The first number in the record

• A way of looking up data in related tables

A foreign key is...

• A unique identifier which links a record to a related record in another table

• A unique identifier for each record in a table

• A shared identifier for all records in one table

What is the primary key?

• Sales ID

• Item ID

• Item Name

• Address

• Payment Complete?