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difference between joinColumn and PrimaryKeyJoinColumni  RSS feed

 
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i have seen these two annotations used when we want to relate two entities.
what i want to know is how one differs from the other..
 
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Hi

You can use joinColumn to define a join column in the table that references the primary key of the associated table.
PrimaryKeyJoinColumn is a little diferent and much easier when the primary key of the related entities are identical, so you do not need to specify a join column.

Regards,
 
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Usage of PrimaryKeyJoinColumn:

(1) For defining linkage to a secondary table:
@SecondaryTable(name="EMP_ADDRESS",
pkJoinColumns=@PrimaryKeyJoinColumn(name="EMP_ID"))

(2)
When no additional foreign key column in either table.In this case, @PrimaryKeyJoinColumn is used instead of an @JoinColumn annotation.


Usage of JoinColumn:

A relationship mapping where one table has a reference to another table.
i.e existence of foreign key column. In JPA its called join columns and
@JoinColumn annotation is the primary annotation used to configure these types of columns. Eg:

 
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