IT234-01

August 4, 2015

Unit 1 assignment

Professor August

1: Correctly identifies the entity name and the entity type

An independent entity has a primary key that comprises attributes of that entity only.

A dependent entity has a primary key that includes at least one attribute which is a foreign key, i.e.

primary key of another entity, dependent entity would be deleted if the independent entity it depends on is deleted.

An external entity is an entity with which the database exchanges data – sending to, receiving from, or both.

Entity Name Entity Type

Student Independent

Locker Independent

Course Number Independent

Instructor Independent

Location Independent

Term Independent

Register Dependent

Section Dependent

2 : Correctly identifies the primary keys for each entity.

Consider every entity you have identified above.

Entity Name

Primary Key

Student

Student ID

Course

Course ID

Locker

Locker ID

Instructor

Instructor ID

Location

Location ID

Term

Term ID

Register

Register ID

Course ID

Student ID

Term ID

Section

Section ID

Date/Time

3: Correctly identifies any corresponding foreign keys

Consider every entity you have identified. Use ‘none’ if no foreign keys are required. There may be more than one foreign key for an entity.

Entity Name

Foreign keys

Student

None

Course

none

Locker

Student ID

Instructor

None

Location

None

Term

None

Register

Course ID

Student ID

Term ID

Section

Instructor ID

Location ID

4: Correctly identifies entities, the relationship(s) between them, and their degree.

Remember that relationships may differ by direction, so you may need another entry.

For example: order only has one customer, but a customer may have many orders. 1 to 1, 1 to many, many to many, none to many, etc.

You may use abbreviations such as 1:1, 1:M, M:M

Entity Name

Entity Name

Relationship

Student

Locker

Register

1:1

1:

M

Course

Register

Section

M

1:

1:

M

Locker

Student

1:1

Instructor

Section

1:

M

Location

Section

1:

M

Term

Register

1:

M

Register

Student

M:1

Section

5: Correctly identifies the intersection table(s) and the attributes

Example from the textbook:

Movie Rental: Movie ID (FK), Copy Number (FK), Transaction ID (FK)

Intersection Entity

Attributes

Register

Course ID

Term ID

Student ID

Section

Instructor ID

Location ID

Powered by TCPDF (www.tcpdf.org)