Conversion of ER Model to Relational Model-Questions
Question 1 :
Consider the following ER Diagram –
a) How many minimum number of tables required ?
Solution :
Step 1 : Conversion of Strong Entities :
Primary Key : A
Primary Key : B
Step 2 : Conversion of Weak Entity :
Primary Key : BC
Step 3 : Conversion of Many to One relationship –
Primary Key : A
Foreign Key : B
So, the minimum number of tables required for the ER Diagram will be as follows –
==> 3 tables
b) Which is the common attribute set of each of minimasation table?
Solution :
Attribute B is common in all the tables.
Question 2 :
Movie(id, title, yr) & Actor(id, name, age)
can we join these tables if there is no foreign key given ?
Solution : NO
Question 3 :
E(B,E,F) & R(A,C,D) where,
B: Primary Key of Table E.
A: Primary key for table R and foreign key of table E.
Is it possible to minimize?
Solution :
Yes, ER(B,E,F,C,D) . It is possible to minimize.
Question 4 :
Consider the following ER Diagram and minimize it into relations.
Solution :
Minimize the ER Diagram into Relations –
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