4.1 Define tables matching to this information using SQL statements to cover as many of the constraints as feasible. (10 Marks) 4.2 List the duties of a Database Administrator (DBA). (5 Marks) 4.3 Does the DBA still need to know about query optimization if we presume that the DBA will never execute his/her own queries? Why? (10 Marks) Study the scenario and complete the question(s) that follow: Entity Relationship Consider a triple association (K) among X, Y, and Zentity sets, where X and Y each have a key constraint and X has 100% involvement X has two characteristics, x1 and x2, with x1 being the key, Y and Z are comparable. K does not have any descriptive properties