CODEWITHSUNDEEP
javaspring-boothibernatejpa
KRISTIJAN TOMASINI
KRISTIJAN TOMASINI

Reputation: 459

Why does 'delete()' method in CrudRepository require entity with unique id?

In the description of the delete method in org.springframework.data.repository,CrudRepository interface it is written only that it deletes a given entity and that it accepts entity object itself.

It specifies nothing about entity's id needing to be unique.

However, this method works only when entity has an unique id. If the table may have multiple rows with the same id, this method fails when entity whose id is not unique is attempted to be deleted (at least in my case).

Now I understand that it is a very bad thing that an id is not unique in the table, but, in theory, it should work since this method accepts the entire entity as a parameter, and every entity (when all its columns are combined) in my table is unique. There are no two identical rows in a table since table has an unique constraint on a combination of all its columns.

Sure, there are other methods, like deleteById which would fail since they only accept id as a parameter and not the whole entity and since id is not unique, Spring does not know which entity to delete. Sure.

But why delete method fails when it should be able to distinguish between entities with the same id since it accepts the whole entitiy as a parameter (thus giving it access to all other columns of the entity and not just the id column)?

Upvotes: 0

Views: 131

Answers (1)

Christian Beikov
Christian Beikov

Reputation: 16400

The requirement for the JPA id is that it is a primary key i.e. uniquely identifies the row. If you do not follow this, bad things will happen. You can have a composite primary key though, as it seems your row is identified by multiple columns. Look into @Embeddable/@EmbeddedId mappings for this purpose.

Upvotes: 2

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