employee (ID, person_name, street, city) works (ID, company_name, salary) company (company_name, city) Figure 2.17 Employee database. 8 Consider the employee database of Figure 2.17. Give an expression in the relational algebra to express each of the following queries: a. Find the ID and name of each employee who does not work for "BigBank". b. Find the ID and name of each employee who earns at least as much as every employee in the database