ERD & EERD

What is ER model?

• The conceptual database as viewed by the end user

• The architecture of database as viewed by the end user

• The database’s main components – entities, cardinality, connectivity

• The database’s main components – entities, attributes, relationships

This is relationship degree for ...

• Binary relationship

• Ternary relationship

• Unary relationship

• Secondary relationship

The semantic net shows ...

• 1:1 relationship

• 1:0 relationship

• 1:M relationship

• M:N relationship

Identify the correct business rules

• A lecturer may teaches one course.

  A course is taught by zero or one lecturer

• A lecturer may teaches zero or one course.

  A course is taught by only one lecturer

• A lecturer may teaches zero or one course.

  A course is taught by many lecturers

• A lecturer may teaches one course.

  A course is taught by zero or one lecturer

Identifies more specific entity subtypes from higher-level entity supertype

Identifies more generic entity supertype from lower-level entity subtypes

Identify the CORRECT info about "Generalization"

• Bottom-up process

• Top-down process

• Based on grouping unique characteristics and relationships of the subtypes

• Based on grouping common characteristics and relationships of the subtypes