Optional one-to-one mapping in Hibernate

java database hibernate one-to-one
hibernate picture hibernate · May 6, 2010 · Viewed 26.4k times · Source

How do I create an optional one-to-one mapping in the hibernate hbm file? For example, suppose that I have a User and a last_visited_page table. The user may or may not have a last_visited page. Here is my current one-to-one mapping in the hbm file:

User Class:

<one-to-one name="lastVisitedPage" class="LastVisitedPage" cascade="save-update">

LastVisitedPage Class:

<one-to-one name="user" class="user" constrained="true" />

The above example does not allow the creation of a user who does not have a last visited page. A freshly created user has not visited any pages yet. How do I change the hbm mapping to make the userPrefs mapping optional?

Answer

Pascal Thivent picture Pascal Thivent · May 6, 2010

To my knowledge, Hibernate doesn't support optional one-to-one (see HHH-2007) so you'll have to use a fake many-to-one with not-null="false" instead.

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