I am little confused. Say in a question its asked to find out the minimum number of tables to represent ER Diagram and nothing says about whether in 1nf or 2nf then what assumption should i take.
I suppose it should be in 1nf cuz its the minimum requirment to be followed. Now in this Question : https://gateoverflow.in/390/gate2008-82
Cant we merge M and P together because there is a total participation on M side the merged relation can have null values but the primary key(i.e. the key attribute M which is M1) won't hence it satisfies 1nf.Likewise then Entire this new Relation can be merged with N with the same logic. Then why is the answer 3.
If we think by another logic which is :-
Since M is on total participation side. The Relation R1 will have the Key(M1,P1),M1 being the Primary key and we can merge the relation with M hence total 2 tables. i.e. (M+R1) and P, likewise we can merge N with R2 but first the primary key of P1 will be inherited by the Relation N. Hence total 3 tables
Now which way to think and why ?