Question

Consider the code in
How do I delete all JPA entities?
The documentation here http://download.oracle.com/docs/cd/E17410_01/javaee/6/tutorial/doc/gjitv.html
describes only queries.

Answer 1

The documentation of the Criteria API describes only queries because the Criteria API is not made for DDL operations. Actually, I’d even say that the whole JPA API is not really made for that.

And by the way, the code of the other question doesn’t show DDL operations, it’s shows bulk DML operations which are described in the JPA 2.0 specification:

4.10 Bulk Update and Delete Operations

Bulk update and delete operations
apply to entities of a single entity
class (together with its subclasses,
if any). Only one entity abstract
schema type may be specified in the
FROM or UPDATE clause.

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

delete_statement ::= delete_clause [where_clause] 
delete_clause ::= DELETE FROM entity_name [[AS] identification_variable]

The syntax of the WHERE clause is
described in Section 4.5.

A delete operation only applies to
entities of the specified class and
its subclasses. It does not cascade to
related entities.

The new_value specified for an
update operation must be compatible in
type with the field to which it is
assigned.

Bulk update maps directly to a
database update operation, bypassing
optimistic locking checks. Portable
applications must manually update the
value of the version column, if
desired, and/or manually validate the
value of the version column.

The persistence context is not
synchronized with the result of the
bulk update or delete.

Caution should be used when executing bulk update or delete operations
because they may result in
inconsistencies between the database
and the entities in the active
persistence context. In general, bulk
update and delete operations should
only be performed within a transaction
in a new persistence context or before
fetching or accessing entities whose
state might be affected by such
operations.

Examples:

DELETE
FROM Customer c
WHERE c.status = ‘inactive’

DELETE
FROM Customer c
WHERE c.status = ‘inactive’
AND c.orders IS EMPTY

UPDATE customer c
SET c.status = ‘outstanding’
WHERE c.balance < 10000