my_result.c

unix上的ODBC实现

/***************************************************************************
                          my_result.c  -  description
                             ---------------------
    begin                : Wed Sep 8 2001
    copyright            : (C) MySQL AB 1995-2002, www.mysql.com
    author               : venu ( [e-mail] )
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *  This is a basic sample to demonstrate how to get the resultset         *
 *  using  MySQL ODBC 3.51 driver                                          *
 *                                                                         *
 ***************************************************************************/

#include "my_utility.h" /* MyODBC 3.51 sample utility header */

/********************************************************
* result set demo                                       *
*********************************************************/
void my_resultset(SQLHDBC hdbc, SQLHSTMT hstmt)
{
  SQLRETURN   rc;
  SQLUINTEGER nRowCount=0, pcColDef;
  SQLCHAR     szColName[MAX_NAME_LEN];
  SQLCHAR     szData[MAX_COLUMNS][MAX_ROW_DATA_LEN]={0};
  SQLSMALLINT nIndex,ncol,pfSqlType, pcbScale, pfNullable;

  printf("\nmy_resultset:\n");

    /* drop table 'myodbc3_demo_result' if it already exists */
    rc = SQLExecDirect(hstmt,"DROP TABLE if exists myodbc3_demo_result",SQL_NTS);
    mystmt(hstmt,rc);

    /* commit the transaction */
    rc = SQLEndTran(SQL_HANDLE_DBC, hdbc, SQL_COMMIT); 
    mycon(hdbc,rc);

    /* create the table 'myodbc3_demo_result' */
    rc = SQLExecDirect(hstmt,"CREATE TABLE myodbc3_demo_result(\
                              id int primary key auto_increment,\
                              name varchar(20))",SQL_NTS);
    mystmt(hstmt,rc);

    rc = SQLEndTran(SQL_HANDLE_DBC, hdbc, SQL_COMMIT);
    mycon(hdbc,rc);    

    /* insert 2 rows of data */    
    rc = SQLExecDirect(hstmt,"INSERT INTO myodbc3_demo_result values(\
                              1,'MySQL')",SQL_NTS);
    mystmt(hstmt,rc);
    
    rc = SQLExecDirect(hstmt,"INSERT INTO myodbc3_demo_result values(\
                              2,'MyODBC')",SQL_NTS);
    mystmt(hstmt,rc);

    /* commit the transaction */
    rc = SQLEndTran(SQL_HANDLE_DBC, hdbc, SQL_COMMIT); 
    mycon(hdbc,rc);

    /* update second row */    
    rc = SQLExecDirect(hstmt,"UPDATE myodbc3_demo_result set name=\
                              'MyODBC 3.51' where id=2",SQL_NTS);
    mystmt(hstmt,rc);

    /* commit the transaction */
    rc = SQLEndTran(SQL_HANDLE_DBC, hdbc, SQL_COMMIT); 
    mycon(hdbc,rc);

    /* now fetch back..*/   
    rc = SQLExecDirect(hstmt,"SELECT * from myodbc3_demo_result",SQL_NTS);
    mystmt(hstmt,rc);

    /* get total number of columns from the resultset */
    rc = SQLNumResultCols(hstmt,&ncol);
    mystmt(hstmt,rc);

    printf(" total columns in resultset:%d\n\n",ncol);

    /* print the column names  and do the row bind */
    for(nIndex = 1; nIndex <= ncol; nIndex++)
    {
      rc = SQLDescribeCol(hstmt,nIndex,szColName, MAX_NAME_LEN+1, NULL,
                          &pfSqlType,&pcColDef,&pcbScale,&pfNullable);
      mystmt(hstmt,rc);

      printf(" %s\t",szColName);

      rc = SQLBindCol(hstmt,nIndex, SQL_C_CHAR, szData[nIndex-1],
                      MAX_ROW_DATA_LEN+1,NULL);
      mystmt(hstmt,rc);
    }

    printf("\n--------------------\n");

    /* now fetch row by row */
    rc = SQLFetch(hstmt);
    while(rc == SQL_SUCCESS || rc == SQL_SUCCESS_WITH_INFO)
    {
       nRowCount++;
       for(nIndex=0; nIndex< ncol; nIndex++)
         printf(" %s\t",szData[nIndex]);
     
       printf("\n");
       rc = SQLFetch(hstmt);
     }
     SQLFreeStmt(hstmt,SQL_UNBIND);

     printf("\n total rows fetched:%d\n",nRowCount);

     /* free the statement row bind resources */
     rc = SQLFreeStmt(hstmt, SQL_UNBIND);
     mystmt(hstmt,rc);

     /* free the statement cursor */
     rc = SQLFreeStmt(hstmt, SQL_CLOSE);
     mystmt(hstmt,rc);
     printf(" success!!\n");
}

/********************************************************
* main routine                                          *
*********************************************************/
int main(int argc, char *argv[])
{
  SQLHENV    henv;
  SQLHDBC    hdbc; 
  SQLHSTMT   hstmt;
  SQLINTEGER narg;
  
    /*
     *  show the usage string when the user asks for this
    */    
      printf("***********************************************\n");
      printf("usage: my_result [DSN] [UID] [PWD] \n");  
      printf("***********************************************\n");      

    /*
     * if connection string supplied through arguments, overrite
     * the default one..
    */
    for(narg = 1; narg < argc; narg++)
    {     
      if ( narg == 1 )
        mydsn = argv[1];
      else if ( narg == 2 )
        myuid = argv[2];
      else if ( narg == 3 )
        mypwd = argv[3];      
    }   

    /* 
     * connect to MySQL server
    */
    myconnect(&henv,&hdbc,&hstmt); 

    /* 
     * simple resultset demo
    */
    my_resultset(hdbc, hstmt);

    /* 
     * disconnect from the server, by freeing all resources
    */
    mydisconnect(&henv,&hdbc,&hstmt);

  return(0);
}