16.2.2. Using stored procedures for querying
Hibernate 3 introduces support for queries via stored procedures and functions. Most of the following documentation is equivalent for both. The stored procedure/function must return a resultset as the first out-parameter to be able to work with Hibernate. An example of such a stored function in Oracle 9 and higher is as follows:
CREATE OR REPLACE FUNCTION selectAllEmployments
RETURN SYS_REFCURSOR
AS
st_cursor SYS_REFCURSOR;
BEGIN
OPEN st_cursor FOR
SELECT EMPLOYEE, EMPLOYER,
STARTDATE, ENDDATE,
REGIONCODE, EID, VALUE, CURRENCY
FROM EMPLOYMENT;
RETURN st_cursor;
END;
To use this query in Hibernate you need to map it via a named query.
<sql-query name="selectAllEmployees_SP" callable="true">
<return alias="emp" class="Employment">
<return-property name="employee" column="EMPLOYEE"/>
<return-property name="employer" column="EMPLOYER"/>
<return-property name="startDate" column="STARTDATE"/>
<return-property name="endDate" column="ENDDATE"/>
<return-property name="regionCode" column="REGIONCODE"/>
<return-property name="id" column="EID"/>
<return-property name="salary">
<return-column name="VALUE"/>
<return-column name="CURRENCY"/>
</return-property>
</return>
{ ? = call selectAllEmployments() }
</sql-query>
Notice stored procedures currently only return scalars and entities. <return-join>
and <load-collection>
are not supported.
16.2.2.1. Rules/limitations for using stored procedures
To use stored procedures with Hibernate the procedures/functions have to follow some rules. If they do not follow those rules they are not usable with Hibernate. If you still want to use these procedures you have to execute them via session.connection()
. The rules are different for each database, since database vendors have different stored procedure semantics/syntax.
Stored procedure queries can't be paged with setFirstResult()/setMaxResults()
.
Recommended call form is standard SQL92: { ? = call functionName(<parameters>) }
or { ? = call procedureName(<parameters>}
. Native call syntax is not supported.
For Oracle the following rules apply:
For Sybase or MS SQL server the following rules apply:
-
The procedure must return a result set. Note that since these servers can/will return multiple result sets and update counts, Hibernate will iterate the results and take the first result that is a result set as its return value. Everything else will be discarded.
-
If you can enable SET NOCOUNT ON
in your procedure it will probably be more efficient, but this is not a requirement.