How to call stored procedures (ODBC)

When an SQL statement calls a stored procedure using the ODBC CALL escape clause, the Microsoft® SQL Server™ driver sends the procedure to SQL Server using the remote stored procedure call (RPC) mechanism. RPC requests bypass a lot of statement parsing and parameter processing in SQL Server and are faster than using the Transact-SQL EXECUTE statement.

To run a procedure as an RPC

1. Construct an SQL statement that uses the ODBC CALL escape sequence. The statement uses parameter markers for each input, input/output, and output parameter, and for the procedure return value (if any):

   {? = CALL procname (?,?)}

     

2. Call SQLBindParameter for each input, input/output, and output parameter, and for the procedure return value (if any).
3. Execute the statement with SQLExecDirect.

Note If an application submits a procedure using the Transact-SQL EXECUTE syntax (as opposed to the ODBC CALL escape sequence), the SQL Server ODBC driver passes the procedure call to SQL Server as an SQL statement rather than as an RPC. Also, output parameters are not returned if the Transact-SQL EXECUTE statement is used.

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