InfoErModel.txt

Er diagram : doesnt have any important info , so we dont need it

 1 ,Er diagram  version1 : Er model for employee only. Employee entity is didiveded into twoo internal Employee and external Employee.

2,Er diagram version 2: a person tables is created as mister haralld recommanded. and the sudent table and Employee table are created with thier relation ship to employee

3, Er diagram version 3: All the tables are connected in Er model , tables are : person, student, employee , internal and external employees.

4 Er diagram version 4,: Additional table is created for the ternary relation ship between student , grade and registration,

5, Er diagram version 5, End of the Er diagram, additional table is introduced between lesson and location coz the relation ship was many to many.

6,Er diagram version 5:( logical model) all the primary keys and their relation ship is identified.