DB2 Version 9.7 for Linux, UNIX, and Windows

Default values and named arguments promote flexibility for creating and calling procedures and functions

Starting in Version 9.7, you can create procedures and specify default values for parameters. When calling procedures, arguments can be assigned to parameters by name, allowing you to pass named arguments in any order.

Starting with Version 9.7 Fix Pack 2, the features of default values and named arguments has been extended to user-defined functions (UDFs).

With default parameter values defined in the procedure or UDF, and the ability to invoke a procedure or UDF with named arguments, you now have the following options when calling the procedure or UDF:

Explicitly use the name of the parameter to name the argument
Omit argument values such that the default value will be assigned
Specify named arguments in any order

These enhancements allow for replacing an existing procedure or UDF with added parameters using defaults such that existing invocations of the procedure or UDF do not need to be changed.

You can use the defaultparam.db2 sample program to learn how to use this feature.

Examples

Example 1: Create a procedure FOO with 3 parameters (parm1, parm2 and parm3) and assign default values for each parameter.
```
CREATE PROCEDURE FOO(parm1 INT DEFAULT -1, parm2 INT DEFAULT -2, parm3 INT DEFAULT -3)
```
Example 2: Invoke the FOO procedure by explicitly including parameter names.
```
CALL FOO (parm1=>10, parm2=>20, parm3=>30)
```
The invocation of FOO is identical to FOO (10, 20, 30).

Example 3: Invoke the FOO procedure by omitting argument values.
```
CALL FOO (40)
```
FOO is invoked using a value of 40 for parm1 and uses the default values of -2 for parm2 and of -3 for parm3.

Example 4: Invoke the FOO procedure by passing arguments to the named parameters in any order.
```
CALL FOO (parm3=>30, parm2=>20)
```
FOO is invoked using the default value of -1 for parm1, the value 20 for parm2 and the value 30 for parm3.

Example 5: Invoke the FOO procedure by passing a mixture of named and unnamed arguments. Values that are not passed in by name are mapped according to their position in the invocation.
```
CALL FOO (40, parm3=>10)
```
FOO is invoked using a value of 40 for parm1, the default value of -2 for parm2, and a value of 10 for parm3.