Explain foreign keys and how they enforce referential integrity
This question tests knowledge of relationships and data consistency enforcement.
Why Interviewers Ask This
Referential integrity is fundamental to relational databases. Interviewers want to ensure you understand how to prevent orphan records and maintain valid relationships.
How to Answer This Question
Define foreign key as a column referencing a parent table's key. Explain it prevents actions creating orphan rows. Mention cascading options if applicable.
Key Points to Cover
- Reference to parent key
- Prevents orphan records
- Enforces consistency
- Cascading effects
Sample Answer
A foreign key is a column in a child table that references a primary or unique key in a parent table. It enforces referential integrity by preventing actions that would create orphan rows, ensuring child values actually…
Common Mistakes to Avoid
- Confusing with primary key
- Ignoring delete rules
- Not explaining integrity
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