SELECT-INTO prepared statement?

Question

Hi,
I have a single-row select to execute. I don't know if the multi-row select functionality (ResultSets, etc.) should be used for a single-select.
Here's from the Oracle JDBC Documentation on a prepared statement with input variables:
PreparedStatement pstmt =
conn.prepareStatement ("insert into EMP (EMPNO, ENAME) values (?, ?)");
pstmt.setInt (1, 1500); // The first ? is for EMPNO
pstmt.setString (2, "LESLIE"); // The second ? is for ENAME
pstmt.execute ();
What I would like to do is have a PreparedStatement for output variables in a SELECT-INTO:
pstmt= conn.prepareStatement("select max(sal) into ? from emp;");
but there appears to be no bind variable functionality.
Callable statements apparently are only for stored procedures.
Basically, should I just use the multirow select for this?
Thanks,
Glen

Answer 1

pstmt= conn.prepareStatement("select max(sal) into ?
from emp;");
but there appears to be no bind variable
functionality.You might be able to bind this as an output parameter, but it seems like extra work (just getting a ResultSet for "select max(sal) from emp" would be a lot more straight forward).
>
Callable statements apparently are only for stored
procedures.Not really, I execute PL/SQL blocks using prepared statements all the time. Sometimes it's the only way to get the data into a format that JDBC can handle.
Here's an example:
    /** This is the SQL used to call the API ... */
    public static final String spSQL =  
    "declare " +
        "t_warranty_tbl apps.cib_devo_wrapper.wartbltyp; " +
        "x_warranty_tbl apps.cib_devo_wartbltyp; " +
        "x_return_text VARCHAR2(2000); " +
    "begin " +
        "apps.cib_devo_wrapper.cib_get_warranty_info(" +
            "P_SERIAL_NUMBER => ?,"
            "X_WARRANTY_TBL => t_warranty_tbl," +
            "X_RETURN_TEXT => x_return_text," +
            "x_row_count => ?); " +
        // Convert to a table of objects ...
        "x_warranty_tbl := apps.cib_devo_wrapper.cib_warranty_casttowartbltyp(t_warranty_tbl); " +
        // Get the cursor with order by ...
        "OPEN ? FOR SELECT * FROM TABLE(CAST(x_warranty_tbl AS apps.CIB_DEVO_WarTblTyp)) tbl " +
            "WHERE tbl.entitlementReturnCode != apps.cib_devo_wrapper.g_ent_ret_code_08 " +
            "ORDER BY tbl.INSTALLEDAT_CUSTOMER_NAME, tbl.SITE_NAME, tbl.SITE_ID, " +
                      "tbl.PRODUCT_FAMILY, tbl.PRODUCT_NAME, tbl.SERIAL_NUMBER; " +
       "?:=x_return_text; " +
    "end;";In this example, I declare a few variables, call a stored procedure,
do some more PL/SQL to reduce the results before I finally bring them back.
The first placeholder (question mark) is the input serial number, the second one is an output parameter that gives the row count. The third
question mark is the cursor that contains the data I need, and the fourth is a reference to a status message.
As you can see, the PL/SQL isn't exclusively stored procedure calls.
>
Basically, should I just use the multirow select for
this?I think you'd need code that looks something like:
DECLARE
myCount NUMBER;
BEGIN
select max(sal) into myCount
from emp;
? := myCount
END;Although wrapping the select in a BEGIN..END block may be enough.