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Explain the key constraints and constraints on Null Values
with examples?

Answer Posted / amit

hi ,

key constraits i.e. referential integerity means

all values in foreign key must be in primary key , but it
may happnes that NULL values may be in foreign key , but
not in primary key .

this is done to cater some of the exception conditions.

Is This Answer Correct ?    4 Yes 1 No



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