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Let E1 and E2 be two entities and R is a relation between E1 and E2, then what is the minimum no of tables required to represent E1, E2 and R if - 

  1. E1 and E2 have 1:m cardinality(E1 on 1 side, E2 on m side); E1 has total participation and E2 has partial participation.
  2. E1 and E2 have 1:m cardinality(E1 on 1 side, E2 on m side); E1 has partial participation and E2 has total participation.
  3. E1 and E2 have 1:m cardinality(E1 on 1 side, E2 on m side); both E1 and E2 have partial participation.
  4. E1 and E2 have 1:m cardinality(E1 on 1 side, E2 on m side); both E1 and E2 have total participation.
  5. E1 and E2 have m:n cardinality; E1 has total participation and E2 has partial participation.
  6. E1 and E2 have m:n cardinality; both E1 and E2 have partial participation.
  7. E1 and E2 have m:n cardinality; both E1 and E2 have total participation.

I am not able to find a single solution for this. Kindly help.

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1) if relationship is many to many and both entities are partially participation

        you can't merge ===> require 3 tables

2) if relationship is many to many and  either of the entities are partially participation but not both side

        you can't merge ===> require 2 tables

3) if relationship is many to many and both entities are total participation

        you can merge all in one table and key of the relation is pk(E1)+pk(E2) but data is redundant and so many partial functional dependencies you get but not transitive dependencies

Why we do normalization ? 

   By normalization tables get increased then what you achieved by merging the tables


1) if relationship is many to one and both entities are partially participation

        you can't merge in one table  ===> 2 tables required

2) if relationship is many to one and many side entity is only partially participation

        you can merge in one table  ===> redundancy and transitive dependencies get but not partial functional dependencies.  because of pk(new table)=pk(E1)

3) if relationship is many to one and one side entity is only partially participation

        you can't merge in one table ===> 2 tables required

4) if relationship is many to one and both entities are totally participation

you can merge in one table  ===> redundancy and transitive dependencies get but not partial functional dependencies.  because of pk(new table)=pk(E1)


1) if relationship is one to one and both entities are partially participation

        you can't merge in one table ===> require 2 tables

2) if relationship is one to one and  either of the entities are partially participation

        you can merge in one table ===> but pk of resultant table should be pk of partial participation otherwise you require 2 tables.

3) if relationship is one to one and both entities are total participation

        you can merge all in one table and pk(new table)=either pk(E1) or pk(E2) is sufficient.




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