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SingaporeComputer ScienceQuick questions
Data, Information and Databases
Quick questions on Relational database design explained: H2 Computing
5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What are primary keys?Show answer
A primary key uniquely identifies each row. It must be unique across rows and never null. A good primary key is stable (does not change) and minimal. Often a dedicated surrogate identifier such as MemberID is used because natural values like names can repeat or change.
What is referential integrity?Show answer
Referential integrity is the rule that every foreign-key value must match an existing primary-key value (or be null where allowed). It prevents:
What is q1?Show answer
State two properties a primary key must have. [2 marks]
What is q2?Show answer
In a one-to-many relationship between Department and Employee, where does the foreign key go and why? [2 marks]
What is q3?Show answer
Give one thing referential integrity prevents. [1 mark]
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