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

Entity relationships can be:

• One-to-One

• Many-to-Many

• Many-to-One

• One-to-Many

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

• One-to-One

• One-to-Many

• Many-to-Many

• Many-to-One

In a hospital system, the relationship between a consultant to a student 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 pupil 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