Answer the following questions in your own words -

1. Define what composite attribute type is. Why is a composite attribute problematic?

2. What is a foreign key? And in what ways is it helpful to have foreign keys?

3. Is it true that every relation has a primary key? In either case of YES or NO, justify your answer.

4. How would you check to see if "two given tables are identical" using a SQL query? Write a sample SQL query and provide a brief explanation (of how the query works to check if the two given tables are identical). 5. Is it possible to convert any SQL query into an equivalent relational algebraic expression (assuming relational algebra can support multi-sets)? In either case of YES or NO, justify your answer.