What are the different types of keys in relational models?
This DBMS question explores primary, foreign, candidate, and super keys. It tests structural understanding of database relationships.
Why Interviewers Ask This
Keys define relationships and constraints in databases. Interviewers assess your ability to model data correctly. Misunderstanding keys leads to poor schema design and integrity issues.
How to Answer This Question
Define each key type clearly. Explain how primary keys uniquely identify records. Describe foreign keys for linking tables. Differentiate between candidate and super keys.
Key Points to Cover
- Primary key uniqueness
- Foreign key relationships
- Candidate key selection
- Super key definition
Sample Answer
Primary keys uniquely identify rows in a table. Foreign keys link tables by referencing another table's primary key. Candidate keys are potential primary keys. Super keys are any set of attributes that uniquely identifie…
Common Mistakes to Avoid
- Confusing candidate and primary keys
- Forgetting composite keys
- Vague relationship descriptions
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