This annotation specifies a database--specific query hint.

You can set up a pessimistic lock and the cache functionality of the entity.

The applicable target is the hints element of @NamedQuery or @NamedNativeQuery.

The following table lists the elements of @QueryHint:

Element name	Optional/Required	Element description
name	Required	This element specifies the name of the hint.
value	Required	This element specifies the value of the hint.

The details of attributes that are supported with Cosminexus JPA provider are as follows:

(a) name element

Type

String

Description

This element specifies the name of the hint to be used. The following value can be specified:

cosminexus.jpa.pessimistic-lock

This is the name of the hint that specifies whether or not to use a pessimistic lock.

Default value

None

(b) value element

Type

String

Description

This element specifies the value of the hint. The following values are specified based on the name of the hint specified in the name element:

Specification value when cosminexus.jpa.pessimistic-lock is specified in the name element

• NoLock: Specified when the pessimistic lock is not used.
• Lock: Specified when the pessimistic lock is used. If the target table is already locked, unlocking is awaited. The SQLs issued at this point are specified as follows, for each used database:
  In Oracle: SELECT.... FOR UPDATE
  In HiRDB: SELECT....WITH EXCLUSIVE LOCK
  
• LockNoWait: Specified when the pessimistic lock is used. If the target table is already locked, an exception occurs. The SQLs issued at this point are specified as follows, for each used database:
  In Oracle: SELECT.... FOR UPDATE NO WAIT
  In HiRDB: SELECT....WITH EXCLUSIVE LOCK NO WAIT
  

Default value

When cosminexus.jpa.pessimistic-lock is specified in the name element

NoLock