Question

I am working with some old hibernate code, and need to update and create a one to one.

I have a table

Table_1
PK table_1_id
FK table_2_id

Table_2
PK table_2_id

How do I map these in hibernate XML files so that the relationship is unqiue.. I have tried the

<many to one ... unique='true'>

but that does not work as it allows two records from table_1 to reference one row from table_2

Answer 1

This is the proper way, as documented in the documentation.

Hibernate will never prevent two records from table_1 to reference one the same row from table_2. That’s the role of the unique constraint that you should add on the table_2_id column of table_1, in the database.