DATABASE SYSTEMS:

SECTION 1 SHORT QUESTIONS (Compulsory) (25 Marks)

1.1 The relational set operators UNION, INTERSECT and MINUS work properly only when the relations are union-compatible. What does union-compatible mean, and how would you check for this condition? (5 Marks)

1.2 What is the difference between UNION and UNION ALL? Write the syntax for each. (5 Marks)

1.3 Given two tables A and B, where A contains columns (ID, Name) and B contains columns (ID, Age), write a relational algebra expression to select all rows from A where the name starts with "J" and the corresponding ID has a matching row in B where the Age is greater than 18. (5 Marks)

1.4 Given a table G with columns (ID, Name, Age), write a relational algebra expression to select the Name and Age columns of the oldest person in the table. (5 Marks)

1.5 Discuss the two (2) possible outcomes of a transaction. (5 Marks)