Session 2. Welcome : To the fourth learning sequence “ Entity-Relationship Model “ E-R Model Recap : In the previous learning sequences, we discussed the basic definitions of Data base subject.
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Welcome: To the fourth learning sequence
“ Entity-Relationship Model “
Recap : In the previous learning sequences, we discussed the basic definitions of Data base subject.
Present learning: We shall explore the following definitions:
- Purpose of E-R MODEL.
- E-R Diagram.
- Entity & Attributes.
- Teachers are
- Students take
- Teachers advises
Samir Samar Math
Samir Issam Math
* Example of Many-Many Relationship
A customer is associated with several (possibly 0) loans via borrower
A loan is associated with several (possibly 0) customers via borrower
* Example of Many-One relationship
In a many-to-one relationship a loan is associated with several (including 0) customers via borrower, a customer is associated with at most one loan via borrower
* Example of One-One relationship
-A customer is associated with at most one loan via the relationship borrower
A loan is associated with at most one customer via borrower
Date is a function of both the student and the course, not of one alone.
Summary: In this learning sequence, we discussed the principles of Entity- Relationship diagram.