Create an ER model for each of the following descriptions:a)Each company operates four departments, and each department belongs to one company.b)Each department in part (a) employs one or more employees, and each employee works for one department.c)Each of the employees in part (b)may or may not have one or more dependents, and each dependentd)belongs to one employee.e)Each employee in part (c) may or may not have an employment history.f)Represent all the ER models described in (a), (b), (c), and (d) as a single ER mod

Which of the following criteria would make an entity a weak entity? a.) If the primary key is not derived from the parent entity in the relationship b.) If the entity can exist without the entity with which it has a relationship c.) If the primary key of a related entity contains the primary key of the parent entity d.) If the entity has a primary key that is partially derived from the parent entity

Consider the following E-R Diagram: Site manages Staff works in has employs Branch Figure A The attributes of each entity are as follows: Staff Entity's attributes are Staff No, Fname, Lname and Extension No. Branch Entity's attributes are Name, Address, Telephone No. Site Entity's attributes are Site No, Address and Capacity. a) Eliminate each redundant relationship from the E-R Diagram above (Figure A) and justify your answer. (Maximum 200 words).

Draw the Enhanced Entity–Relationship (EER) model and the relational schema for the case study below: This case study describes a company called HomeCinema, which rents out videos to its members. The first branch of HomeCinema was established in 1982 in Jeddah but the company has now grown and has many branches throughout the country. As HomeCinema has grown, so has the difficulties in managing the increasing amount of data used and generated by the company. To ensure the continued success of the company, the Director of HomeCinema has urgently requested that a database application be built to help solve the increasing problems of data management. The data held on a branch of HomeCinema is the branch address made up of street, city, state, and zip code, and the telephone numbers (maximum of 3 lines). Each branch is given a branch number, which is unique throughout the company. Each branch of HomeCinema has staff, which includes a Manager, one or more Supervisors, and a number of other…