Ch2

Question 1

ERM

Answer 1

Is detailed, logical representation of the data for an organization or for business area
Entity , attribute, relationship
Entity relationship data model

Question 2

ERD

Answer 2

Is graphical representation entity relationship model

Entity relationship diagram

Question 3

Problem spearsheet

Answer 3

Redundency
Difficult to accessing reated data
Limited security
Size limitation

Question 4

Redundency means

Answer 4

Duplication of data to the storing the same data in more than one place

Question 5

Natural key

Answer 5

Consists of columns that uniqelty identifies entity

Logical key or intelligent key

Question 6

Secundary key

Answer 6

Columns of interest strictly fot retrieval purpose

Question 7

Forign key

Answer 7

Columns is one table that required to match value of the primary key for some row in another table or is required to be null.

• used to create relationship between table
• used to ebforce certian types of integrity constraint.

Question 8

Artificial key

Answer 8

Columns created for an entity to serve solely as the primary key and that is visible to users

Question 9

Surrogate key

Answer 9

Sysrem-generated usually hidden from users also called synthetic key

Question 10

Primary key

Answer 10

Is unique identifiers key used in relational database designing for keeping unique column record

Question 11

Foreign key

Answer 11

Is primary key used in relational database designing for keeping unique record

Question 12

Composite key

Answer 12

When that is two key used in any database table so one key is primary key and another key worked with primary key