Freeing a Statement Handle
SQL Server Native Client (SNAC) is not supported beyond SQL Server 2012. Avoid using SNAC in new development work, and plan to modify applications that currently use it. The Microsoft ODBC Driver for SQL Server provides native connectivity from Windows to Microsoft SQL Server and Microsoft Azure SQL Database.
It is more efficient to reuse statement handles than to drop them and allocate new ones. Before executing a new SQL statement on a statement handle, applications should verify that the current statement settings are appropriate. These include statement attributes, parameter bindings, and result set bindings. Generally, parameters and result sets for the old SQL statement must be unbound by calling SQLFreeStmt with the SQL_RESET_PARAMS and SQL_UNBIND options and then re-bound for the new SQL statement.
When the application has finished using the statement, it calls SQLFreeHandle to free the statement. Note that SQLDisconnect automatically frees all statements on a connection.