Jpa composite key nullable columns

java hibernate jpa composite-id
Miguel Ping picture Miguel Ping · Mar 23, 2009 · Viewed 13.2k times · Source

I'm using Hibernate's JPA impl to model some tables. I'm having trouble mapping a table that:

  • Has no primary key
  • Has a unique index on 4 columns, 3 of which can be nullable

I tried to hack it and define the index as a composite Id, but since some columns are nullable this is not working properly. Is this possible with JPA/Hibernate?

Thanks

Answer

Kevin Crowell picture Kevin Crowell · Mar 23, 2009

It seems that the column that is not nullable should be your primary key. No parts of a composite key should ever be nullable.

You will need to take the nullable properties and place them outside of your primary/composite key.

Also, this looks like a duplicate of Hibernate mapping a composite key with null values which came up as #3 when I googled "null composite key".

Related questions

How to fix the Hibernate "object references an unsaved transient instance - save the transient instance before flushing" error

I receive following error when I save the object using Hibernate object references an unsaved transient instance - save the transient instance before flushing

Read More
What's the difference between JPA and Hibernate?

I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the difference? I have experience using …

Read More
Difference between FetchType LAZY and EAGER in Java Persistence API?

I am a newbie to Java Persistence API and Hibernate. What is the difference between FetchType.LAZY and FetchType.EAGER in Java Persistence API?

Read More