Stored procedure calls in a Db2 ODBC application

To invoke stored procedures from a Db2 ODBC application, pass a CALL statement to SQLExecDirect(), or to SQLPrepare() followed by SQLExecute().

The syntax of the CALL statement is:

procedure-name

The name of the stored procedure to execute. Call SQLProcedures() to obtain a list of stored procedures that are available at the database.

Although the CALL statement cannot be prepared dynamically, Db2 ODBC accepts the CALL statement as if it can be dynamically prepared. You can also call stored procedures with the ODBC vendor escape sequence.

The question mark (?) in the CALL statement syntax diagram denotes parameter markers that correspond to the arguments for a stored procedure. Call SQLProcedureColumns() to determine the input and output parameters for a stored procedure. You must pass all arguments to a stored procedure with parameter markers. Literals, the NULL keyword, and special registers are not allowed. However, you can use literals if you include a vendor escape clause in your CALL statement.

You bind the parameter markers in a CALL statement to application variables with SQLBindParameter(). Although you can use stored procedure arguments that are both input and output arguments, you should avoid sending unnecessary data between the client and the server. Specify either SQL_PARAM_INPUT for input arguments or SQL_PARAM_OUTPUT for output arguments when you call SQLBindParameter(). Specify SQL_PARAM_INPUT_OUTPUT only if the stored procedure uses arguments that are both input and output arguments. Literals are considered type SQL_PARAM_INPUT only.