One to many relationship between X(one side) and Y(many side) entities in an E-R diagram is converted asa)Modify X side to include foreign key of Y side as primary key.b)Modify Y side to include primary key of X side as foreign key.c)Modify Y side to include foreign key of X side as primary key.d)Modify X side to include primary key of Y side as foreign key.Correct answer is option 'B'. Can you explain this answer?

Question

Answer

Explanation:

In an Entity-Relationship (E-R) diagram, a one-to-many relationship between two entities X and Y indicates that each record in entity X can be associated with multiple records in entity Y, but each record in entity Y can be associated with only one record in entity X.

To represent this one-to-many relationship in an E-R diagram, we need to modify the entities X and Y accordingly. The correct approach is to modify the entity Y to include the primary key of X as a foreign key.

Here's a detailed explanation of why option 'B' is the correct answer:

Option A: Modify X side to include foreign key of Y side as primary key.
- This approach suggests modifying entity X to include the foreign key of Y as its primary key. However, this is incorrect because the primary key of an entity should uniquely identify its own records, not the records of another entity.

Option B: Modify Y side to include primary key of X side as foreign key.
- This is the correct approach. By modifying entity Y to include the primary key of X as a foreign key, we establish the relationship between the two entities. Each record in entity Y can now reference the corresponding record in entity X.

Option C: Modify Y side to include foreign key of X side as primary key.
- This approach suggests modifying entity Y to include the foreign key of X as its primary key. However, this is incorrect because the primary key of an entity should uniquely identify its own records, not the records of another entity.

Option D: Modify X side to include primary key of Y side as foreign key.
- This approach suggests modifying entity X to include the primary key of Y as a foreign key. However, this is incorrect because the foreign key should be used to reference the primary key of another entity, not the other way around.

In summary, the correct approach to represent a one-to-many relationship between entities X and Y in an E-R diagram is to modify entity Y to include the primary key of X as a foreign key.

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