Entity Relationship Diagrams (OCR A-Level Computer Science): Quizzes
📚Quizzes
Practise the questions
12 questions from this quiz
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Practise the questions
12 questions from this quiz
What is the primary purpose of an Entity Relationship Diagram (ERD)?
What is the primary purpose of an Entity Relationship Diagram (ERD)?
To model relational database structure
What is the key characteristic of a primary key in a database table?
What is the key characteristic of a primary key in a database table?
It uniquely identifies each record
What is the main function of a foreign key in a database table?
What is the main function of a foreign key in a database table?
To link to the primary key of another table
How does a secondary key differ from a primary key?
How does a secondary key differ from a primary key?
Secondary keys are not necessarily unique
In a one-to-one (1:1) relationship, how many records in one table link to another?
In a one-to-one (1:1) relationship, how many records in one table link to another?
Each record links to only one record
Which type of relationship is most common in relational databases?
Which type of relationship is most common in relational databases?
One-to-many (1:M)
How is a many-to-many (M:M) relationship implemented in a database?
How is a many-to-many (M:M) relationship implemented in a database?
Creating a junction table
When should a junction table be used in database design?
When should a junction table be used in database design?
For many-to-many relationships
What is a composite primary key in a junction table?
What is a composite primary key in a junction table?
A combination of multiple fields
What shape is used to represent entities in an ERD?
What shape is used to represent entities in an ERD?
Rectangles
Which relationship types use foreign keys to establish direct links between tables?
Which relationship types use foreign keys to establish direct links between tables?
1:1 and 1:M relationships
What is a common mistake when designing ERDs?
What is a common mistake when designing ERDs?
Confusing 1:M and M:M relationships