Jaybird 2.1 JDBC driver Java Programmer's Manual - Firebird

is no measurable performance differences when using the callable statement
interface.
Also the JDBC specification allows another syntax for the stored procedure calls:
CallableStatement stmt = connection.prepareCall(
"{?= call factorial(?}");
stmt.registerOutParameter(1, Types.INTEGER);
stmt.setInt(2, 2);
stmt.execute();
int result = stmt.getInt(1);
Illustration 4.13.: Calling stored procedure using different syntax.
Note, that input parameters have now indices 2 and 3, and not 1 and 2 as in the
previous example. This syntax seems to be more intuitive, as it looks like a
function call. It is also possible to use this syntax for stored procedures that return
more than one parameter by combining code from the second and the last
examples.
Firebird stored procedures can also return result sets. This is achieved by using the
SUSPEND keyword inside the procedure body. This keyword returns the current
values of the output parameters as a single row to the client.
The following example is more complex and shows a stored procedure that
computes a set of factorial of the numbers up to the specified number of rows.
The SELECT SQL statement is the natural way of accessing the selectable
procedures in Firebird. You “select” from such procedures using the Statement
or PreparedStatement objects.
With minor issues it is also possible to access selectable stored procedures
through the CallableStatement interface. The escaped call must include all IN
and OUT parameters. After the call is prepared, parameters are set the same way.
However application must explicitly tell the driver that selectable procedure is
used and access to the result set is desired. This is done by calling a Jaybirdspecific
method as showed in the example below. When this is not done,
application has access only to the first row of the result set.
The getter methods from the CallableStatement interface will provide you
access only to the first row of the result set. In order to get access to the complete
result set you have to either call the executeQuery method or the execute
method followed by getResultSet method.
Chapter 4. Executing statements 48