using Hibernate, I'd like to update a data in the database based on conditions, but I got the following error : "node t开发者_如何学Goo traverse cannot be null"
Here is my database description :
Account: id, email, password
Member : id, account, team
Team: id, current (and a reference to member => members)
Here is my JPA :
UPDATE Team t SET t.current = :current LEFT JOIN t.members m WHERE t.current = :current_true AND m.account = :account
What am I doing wrong? If i move the LEFT JOIN to before the SET :
UPDATE Team t LEFT JOIN t.members m SET t.current = :current WHERE t.current = :current_true AND m.account = :account
I got : "expecting SET, found LEFT"
If I remove the join :
UPDATE Team t SET t.current = :current WHERE t.current = :current_true AND t.members.account = :account
I got : "Illegal attempt to dereference collection".
What is the correct way to update values ?
Thanks for your help!
Use a subquery:
(not tested)
UPDATE Team t SET t.current = :current
WHERE t.id in (select t1.id from Team t1 LEFT JOIN t1.members m WHERE t1.current = :current_true AND m.account = :account)
The JPA 2.0 specification in chapter 4 contains details of all supported features in JPQL. This is the definition of the "update" statement:
The syntax of these operations is as follows:
update_statement ::= update_clause [where_clause]
update_clause ::= UPDATE entity_name [[AS] identification_variable]
SET update_item {, update_item}*
update_item ::= [identification_variable.]{state_field | single_valued_object_field} =
new_value
new_value ::=
scalar_expression |
simple_entity_expression |
NULL
As you can see, support for multiple entities is not stated here. I guess you will have to find a different way to do it, perhaps create a method that selects the entities that you want to update first, and then iterate over the results setting the values. Or you could use a native SQL update.
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