Draw an ER diagram that shows the above two entity types as well as the associative entity types with all the relationships and cardinalities.

ASSIGNMENT

QUESTION 1

Use the following figure to answer this question.

The primary key of the entity type car is ___________________________. Please enter it exactly as it appears on the figure and enter only the attribute name and no other notations like those for the primary key or required attribute..

QUESTION 2

Use the following figure to answer this question.

The primary key of the entity type person is ___________________________. Please enter it exactly as it appears on the figure and enter only the attribute name and no other notations like those for the primary key or required attribute..

QUESTION 3

In the following figure, how many attributes does the entity type car have — you should include any attributes that are shown and those that the entity type implicitly has by virtue of its relationships.

QUESTION 4

In the following figure, how many attributes does the entity type person have — you should include any attributes that are shown and those that the entity type might implicitly have by virtue of its relationships.

QUESTION 5

In the following figure, how many optional attributes does the entity type person have?

QUESTION 6

In the following figure, how many required attributes does the entity type car have? This is a bit involved and goes beyond what was explicitly mentioned in class. Think carefully. Pat yourself on the back if you get it right!

QUESTION 7

In the diagram below, what is the degree of the relationship?

A .m:n

B.1:1

C.1:n

QUESTION 8

In the diagram below, which entity type(s) has/have obligatory participation?

person only

Both car and person

car only

QUESTION 9

Someone created the ER diagram shown below.

Since the diagram has a many to many relationship, they added an associative entity and created the diagram shown below. The relationship line between book and book_author is fully solid since the line on the side of book in the original diagram was solid.

From the above figure, how many attributes does the entity type Book_Author have? Remember to include any implicit attributes as well.

QUESTION 10

Someone created the ER diagram shown below.

Since the diagram has a many to many relationship, they added an associative entity and created the diagram shown below. The relationship line between book and book_author is fully solid since the line on the side of book in the original diagram was solid.

From the above figure, how many required attributes does the entity type Book_Author have? Remember to include any implicit attributes as well.

 QUESTION 11

Someone created the ER diagram shown below.

Since the diagram has a many to many relationship, they added an associative entity and created the diagram shown below. The relationship line between book and book_author is fully solid since the line on the side of book in the original diagram was solid.

What is the primary key for Book_author?. Each option below mentions an attribute name. Select the attribute(s) that make up the primary key for Book_author.

author_id

title

book_id

contract_date

QUESTION 12

Draw an ER diagram (a single ER diagram to capture all of the retirements mentioned) for the following situation:

Every employee is assigned an office. An office might be assigned to one employee or might be empty.

QUESTION 13

Draw an ER diagram (a single ER diagram to capture all of the retirements mentioned) for the following situation:

Each car company might be the manufacturer of many car models or the company could be new and might not have any models yet. Every car model is made by exactly one company.

QUESTION 14

Draw an ER diagram (a single ER diagram to capture all of the retirements mentioned) for the following situation:

An apartment rental company owns many apartment complexes across the country. Each complex has a unique id, complex name, year it was built in and street, city and zip. Each building has a building number, the date it was last painted and the style of the building. The building number is unique within a complex, but not across complexes. Each apartment complex has one or many buildings and each building belongs to exactly one apartment complex. To uniquely identify a building, we need the id of the complex and the building number.

QUESTION 15

The ERD below shows that a supplier might be the supplier of one or many parts, and that a part might be supplied by zero or several suppliers. For example, supplier 1 supplied 200 units of part A on Jan 5, 2011 and supplier 2 supplied 300 units of part B on Feb 1, 2012. Supplier 1 also supplied 150 units of part B and 65 units of part C on March 2011. Part D has not had any shipments so far. For now, assume that we need to store information only about the latest shipment that suppliers made of each part that they supplied.

As we have discussed in class, whenever we have a many to many relationship, we need to create an associative entity type. Draw an ER diagram that shows the above two entity types as well as the associative entity types with all the relationships and cardinalities. You can choose to give the associative entity type its own primary key or use key migration.