Problem

Transform the relational schema developed in Problem and Exercise 9 into an EER diagram....

Transform the relational schema developed in Problem and Exercise 9 into an EER diagram. State any assumptions that you have made.

Reference Problem and Exercise 9

Table 4-5 shows a shipping manifest. Your assignment is as follows:

a. Draw a relational schema and diagram the functional dependencies in the relation.

b. In what normal form is this relation?

c. Decompose MANIFEST into a set of 3NF relations.

d. Draw a relational schema for your 3NF relations and show the referential integrity constraints.

e. Draw your answer to part d using Microsoft Visio (or any other tool specified by your instructor).

Step-by-Step Solution

Solution 1

Step #1 of 3

Transform relational schema to EER (Enhanced Entity-Relationship) diagram

Entity-relationship model:

• It is used to represent data’s logically in business areas or in a service organization.

• It is most commonly used model for the communication between the end users and designers and it is used in the analysis phase of the system development.

• EER diagram is the specialised format of ER diagram.

Assumptions to transform relational schema to EER:

• There are some variations in the transformation.

• The assumptions made in this case are:

o A ship is operated by a captain

o Every shipment has a unique ID.

o Every ship carries consignments with some quantity and some identification number with it.

• Using the above assumptions, an EER diagram is modeled and shown below:

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Step #2 of 3

Cardinality notations in the relationship:

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Step #3 of 3

• In the above ER diagram, the relationship between entities CAPTAIN and SHIPMENT,

o One-to-many relationship is denoted here.

o A captain can be zero or one, who can operate many shipments or zero shipments.

• The relationship between entities SHIPMENT and SHIPMENT LINE,

o One-to-many relationship is denoted here.

o A shipment can handle many quantities.

• The relationship between entities SHIPMENT LINE and ITEM,

o Many-to-one relationship is denoted here.

o Many quantities contain a single item number.

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Solutions For Problems in Chapter 4

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