ODBC SQL NULL conversion

ODBC SQL NULL conversion

• General structure:

Within the Visual C++-code, calls are made to Oracle PL/SQL procedures, stored in a database. To accomplish this, ODBC is used for type conversion. The stored procedures consist of a number of parameters, which can be input, output or input/output parameters. In some cases the input/output parameters require (SQL) NULL values for input. The output value of these parameters could either be a NULL value or a real value.

• ODBC mechanism, and possible solution:

ODBC offers a function, called SQLBindParameter, that can be used to bind application parameters to to parameter markers in a SQL statement. One of the arguments in SQLBindParameter is called PCBVALUE; this (pointer) argument could contain the value SQL_NULL_DATA. This would mean that the PL/SQL parameter receives a SQL NULL value.

• Problem:

It doesn't seem possible to pass an input/output parameter from Visual C++ through ODBC to PL/SQL with the SQL value NULL, not even with the SQLBindParameter function.

• Questions:
  1. Is it possible to pass an input/output parameter from Visual C++ through ODBC towards PL/SQL wich contains a SQL NULL value, and could this parameter then receive a NULL value or a real value?
  2. Must this be done with SQLBindParameter?
  3. If so, how does this work? Could you give an example? -- Ed. Doesburg edd_at_worldonline.nl