Example: Visual C++ - Access and return data by a call to a stored procedure

This example illustrates using Visual C++ to access and return data by a call to a stored procedure.

Only the code relevant to the stored procedure call has been included here. This code assumes the connection has already been established. See Examples: RPG - Host code for ODBC stored procedures for the source code for the stored procedure.

Creating the stored procedure

 //* Drop the old Procedure
 strcpy(szDropProc,"drop procedure apilib.partqry2");
 
 rc = SQLExecDirect(m_hstmt, (unsigned char *)szDropProc, SQL_NTS);
 
 // This statement is used to create a  stored procedure
 // Unless the
 // procedure is destroyed, this statement need never be re-created
 strcpy(szCreateProc,"CREATE PROCEDURE APILIB.PARTQRY2 (INOUT P1 INTEGER," );
 strcat(szCreateProc,"INOUT P2 INTEGER)");
 strcat(szCreateProc,"EXTERNAL NAME APILIB.SPROC2 LANGUAGE RPG GENERAL")
 
 //' Create the new Procedure
 rc = SQLExecDirect(m_hstmt, (unsigned char *)szCreateProc, SQL_NTS);
 if (rc != SQL_SUCCESS &&; rc != SQL_SUCCESS_WITH_INFO) {
  DspSQLError(m_henv, m_hdbc, SQL_NULL_HSTMT);
  return APIS_INIT_ERROR;
 }
 if(rc != SQL_SUCCESS) {
  DspSQLError(m_henv, m_hdbc, SQL_NULL_HSTMT);
        return APIS_INIT_ERROR;
    }

Preparing the statements

// Prepare the procedure call
  strcpy(szStoredProc, "call partqry2(?, ?)");
 // Prepare the stored procedure statement
    rc = SQLPrepare(m_hstmt, (unsigned char *) szStoredProc, strlen(szStoredProc));
    if(rc != SQL_SUCCESS &&; rc != SQL_SUCCESS_WITH_INFO) {
  DspSQLError(m_henv, m_hdbc, m_hstmt);
        return APIS_INIT_ERROR;
    }

Binding the parameters

 // Bind the parameters for the stored procedure
 
rc = SQLBindParameter(m_hstmt, 1, SQL_PARAM_INPUT_OUTPUT, SQL_C_LONG,
   SQL_INTEGER, sizeof(m_lOption), 0, &m_lOption, sizeof(m_lOption), &lcbon),
   &lcbOption);
rc |= SQLBindParameter(m_hstmt, 2, SQL_PARAM_INPUT_OUTPUT, SQL_C_LONG,
   SQL_INTEGER, sizeof(m_lPartNo), 0, &m_lPartNo, sizeof(m_lPartNo), &lcbon),
   &lcbOption);
 
    // Bind the Columns
 rc = SQLBindCol(m_hstmt, 1, SQL_C_SLONG, &m_lSPartNo,
   sizeof(m_lSPartNo), &lcbBuffer);
 rc |= SQLBindCol(m_hstmt, 2, SQL_C_CHAR, &m_szSPartDesc,
   26, &lcbBuffer);
 rc |= SQLBindCol(m_hstmt, 3, SQL_C_SLONG, &m_lSPartQty,
   sizeof(m_lSPartQty), &lcbBuffer);
 rc |= SQLBindCol(m_hstmt, 4, SQL_C_DOUBLE, &m_dSPartPrice,
   sizeof(m_dSPartPrice), &lcbBuffer);
 rc |= SQLBindCol(m_hstmt, 5, SQL_C_DATE, &m_dsSPartDate,
   10, &lcbBuffer);

Calling the stored procedure

 // Request a single record
 m_lOption = ONE_RECORD;
 m_lPartNo = PartNo;
 
 // Run the stored procedure
 rc = SQLExecute(m_hstmt);
    if (rc != SQL_SUCCESS) {
        DspSQLError(m_henv, m_hdbc, m_hstmt);
        return APIS_SEND_ERROR;
    }
 
 // (Try to) fetch a record
 rc = SQLFetch(m_hstmt);
 if (rc == SQL_NO_DATA_FOUND) {
  // Close the cursor for repeated processing
      rc = SQLCloseCursor(m_hstmt);
      return APIS_PART_NOT_FOUND;
 }
 else if (rc != SQL_SUCCESS) {
        DspSQLError(m_henv, m_hdbc, m_hstmt);
        return APIS_RECEIVE_ERROR;
    }
 
 // If we are still here we have some data, so map it back
 // Format and display the data
      .
      .
      .