Conversion of entity sets:
I) For every strong entity type E in the ER diagram, we make a relation R containing all the easy attributes of E. The relation R primary key will be one of the key attributes of R.
For example, the STUDENT, FACULTY, COURSE and DEPARTMENT tables in Figure.
ROLLNO: Primary Key
COURSE_ID: Primary Key
D_NO: Primary Key
For each weak entity type W in the E R Diagram, we make another relation R that have all easy attributes of W. If E is an owner entity of W then key attribute of E is also contained in R. This key attribute of R is set as a foreign key attribute of R. Now the mixture of primary key attribute of owner partial key and entity type of weak entity type will form the key of the weak entity type.
The weak entity GUARDIAN, where the key field of student entity
RollNo has been added.