CHP3

Question 1

What is Data model

Answer 1

• Relatively simple representations, usually graphical. Facilitate interaction among designer and the end user

Question 2

Data Model Basic Building Blocks

Answer 2

1. Entity - data to be collected and stored
2. Attribute - characteristic of an entity
3. Relationship - describes association amongst entities
   such as one-to-one relationship
   many-to-one relationship
   one-to-many relationship
4. Constraint a restriction placed on data such as NOT NULL, PRIMARY KEY

Question 3

Business rules and its source

Answer 3

• Precise descriptions of a policies, procedures, or principles within a specific organisation
• Must be kept up to data and easy to understand
• COMPANY MANAGERS, POLICY MAKERS, WRITTEN DOCUMENTATION

Question 4

What is the entity relationship model?

Answer 4

1. Table
   
   • Consisting of a series of row/column intersections
2. Relational diagram
   
   • representation of the database’s entities, attributes, and relationships between those entities
3. Uses graphic models database components