Hibernate Criteria: Left Outer Join with restrictions on both tables

问题

I am doing a LEFT OUTER JOIN, but I am only able to apply Restrictions on the first table. Is there a way ti apply on the second table as well?

Here is my code:

Criteria criteria = this.crudService
        .initializeCriteria(Applicant.class).setFetchMode("products",
              FetchMode.JOIN);.

This works (applicant has an applicantName property):

criteria.add(Restrictions.eq("applicantName", "Markos")

Neither of these works (product has a productName property)

criteria.add(Restrictions.eq("productName", "product1")

criteria.add(Restrictions.eq("products.productName", "product1") // products: the name of the property criteria.add(Restrictions.eq("Product.productName", "product1") // Product: the name of the DB table

And this is the exception I am receiving saying (if I understand correctly) that the productName property does not exist in Applicant:

EJB Exception: ; nested exception is: org.hibernate.QueryException: could not resolve property: products.inventedName of: org.myCompany.applicant.entity.Applicant; nested exception is: org.hibernate.QueryException: could not resolve property: products.inventedName of: org.myCompany.applicant.entity.Applicant

I tried to use an alias, but this generated an INNER JOIN, instead of the LEFT OUTER JOIN I want.

How can I apply restrictions on both tables?

UPDATE:

Issue is probably the same as this: https://forum.hibernate.org/viewtopic.php?p=2393694

回答1:

You can specify left outer join in the createalias...

.CreateAlias("products", "p", NHibernate.SqlCommand.JoinType.LeftOuterJoin)
.Add(Restrictions.Eq("p.inventedName", inventedName));

Be aware that you are doing a left outer join with a restriction on that column...essentially making it an inner join. If you also want applicants without products then you'll have to check for null product too.

回答2:

Update:

.CreateAlias("products", "p", JoinType.LEFT_OUTER_JOIN)
.Add(Restrictions.Eq("p.inventedName", inventedName));

回答3:

I solved this my problem creating a new criteria and I could use LEFT_OUTER_JOIN in both cases.

来源：https://stackoverflow.com/questions/2208201/hibernate-criteria-left-outer-join-with-restrictions-on-both-tables