ISRO2009-72

Question

Purpose of 'Foreign Key' in a table is to ensure

• A. Null Integrity
• B. Referential Integrity
• C. Domain Integrity
• D. Null and Domain Integrity

Answer 1

Purpose of F.K. in a table is to ensure referential integrity. i.e the f.k of one table can only have the values that are in some unique/primary key of referenced table (or f.k. will have NULL VALUE), it can not have any unmatched values.

Answer 2

 foreign key is a field (or collection of fields) in one table that uniquely identifies a row of another table