Consider a database system with following schemas; Hospital(hname, haddress, hspecilaity) Doctor(did, dname, dspecilization, ) Worksat(did, hname, workinghrs) Pharmacy(phname, hname, no_of_sales, total_revenue) Now write SQL statements and relational algebra statements for following queries: a. Select name of all doctors having specialization 'gyno', b. Select the name and address of hospital where working hours is 'day', c. Using natural join select the name of doctors whose working hours are 'night', d. Find the average salary of the doctors, e. Find names of hospital and their pharmacy which generate revenue more than 10000. Sort the result in descending order on the basis of pharmacy name.[10]

What do you mean by weak entity and partial key? Design an ER diagram for following scenario; In film industry, producers produce movies. Producers have their name, age and budget as attributes. They are uniquely identified by prod_id. All the movies have their title, year, and release date. No movies can have same title. Every movies must be played by actor. An actor can play many movies. Actors have Fname and Lname to uniquely identify them. The actors have charge_rate as well. A single movie can have many producers and a producer can produce many movies. [3+7]

Define serial, non-serial and serilizable schedules with example. How can you test serializability in a schedule, illustrate with an example?[5]