Logical Design

Question 1

3 main phases of database design

Answer 1

Conceptual, Logical, Physical

Question 2

Conceptual database design

Answer 2

The process of constructing a model of the data used in an organisation independent of all physical considerations

Question 3

What is done in a conceptual database design?

Answer 3

Building an ER model identifying entities, relationships, attributes etc

Question 4

Logical database design

Answer 4

Process of constructing a model of data used in an organisation based on a specific data model but independent of a particular DBMS and other physical considerations

Question 5

What is done in a logical database design?

Answer 5

ER model is mapped to a set of relational tables

Question 6

How are relationships represented in tables?

Answer 6

Copying the primary key of the parent into the child where it becomes a foreign key

Question 7

How is cardinality determined?

Answer 7

Looking at the maximum values in the multiplicity ranges on either side of the relationship

Question 8

Left side of the multiplicity range

Answer 8

Participation

Question 9

Right side of the multiplicity range

Answer 9

Cardinality

Question 10

Why do we use the participation?

Answer 10

To merge the entities into a single tables or create separate tables related by a foreign key

Question 11

Mandatory participation on both sides of a 1:1 relationship (1:1, 1:1)

Answer 11

Entities are combined into a single table. Of the original PKs, one becomes the PK for that table and the other becomes the alternate key

Question 12

Mandatory participation of one side of a 1:1 relationship (1:1, 0:1)

Answer 12

Copy the PK and make it the foreign key in the other table

Question 13

Optional participation on both sides of a 1:1 relationship (0:1, 0:1)

Answer 13

Add the PK and make is the FK

Question 14

1:* binary relationship

Answer 14

Copy PK and attributes of relationships on the one side table and paste to the many side table