1. What is a referential integrity constraint? Define the term, and give an example of its use. Are null values allowed in foreign key columns with a referential integrity constraint? How does the...

1. What is a referential integrity constraint? Define the term, and give an example of its use. Are null values allowed in foreign key columns with a referential integrity constraint? How does the referential integrity constraint contribute to database integrity?

2. Explain the role of referential integrity constraints in normalization.

3. Do relations Stud ID _Social Security Number and Social Security Number _Stud Name contain a transitive dependency?