Hibernate一对多连接在两列上

Question

I have a SQL query that closely resembles the following:

select *
from parent p inner join child c on p.id = c.parent_id and c.type = 'PARENT_TYPE';

I am trying to define my entity mappings with a @One-To-Many association so that I can load the parent object and it will automatically load the children. The thing I don't know how to do, is how to properly annotate my entities for this to happen correctly with the second part of the join criteria (ie the c.type = 'PARENT_TYPE' part). I tried using a @FilterDef and then enabling the filter on the session and it worked, but it doesn't seem like the optimal solution.

Answer 1

If you use a join-formula, you will lose other abilities (such as sub-select query fetch optimization). Why aren't the two columns you are joining on part of a key. Introduce an embedded-id type consisting of the two columns and join using that type.