3. consider the following relational schema. an employee can work in more than one department; the pct_time field of the works relation shows the percentage of time that a given employee works in a given department. emp(eid: integer, ename: string, age: integer, salary: real) works(eid: integer, did: integer, pct_time: integer) dept(did: integer, budget: real, managerid: integer) write sql-92 integrity constraints (domain, key, foreign key, or check constraints; or assertions) or sql: 1999 triggers to ensure each of the following requirements, considered independently.