Relational Databases
Computer Science: OCR A Level, topic 3.2.3
Relational Database
A relational database is a set of tables whose records are linked by certain fields.
Relational database
- A relational database is a set of tables whose records are linked by certain fields.
- Each table contains data on one entity e.g. students or parents.
- When you link one table to another, this is known as a relationship.
- Each table then has a relationship to other tables using primary and foreign keys.
Foreign key
- If the primary key of one table is placed into another table, this is then known as a foreign key.
- For example, when a student ID field is added to a parent table to link you to your parents accounts, that student ID is a primary key in the student table but becomes a foreign key in the family table.
- The parents table will have its own primary key.
Secondary key
- A secondary key may also be kept by the database.
- A parent may not know their child’s student ID, but they will be able to locate their last name in the database.
- Secondary keys do not need to be unique.
Test yourself on Relational Databases
What do we call the primary key of one table when it is placed into another table?
A venue uses a relational database to keep track of bookings.
What is the primary key of the bookings table?A venue uses a relational database to keep track of bookings.
What is the primary key of the members table?