/*******************************************

*****  函数功能 :

*****      抽取数据库记录

*****

********************************************/

int extract_data(char *efilename,const char *sqlname)

{

  FILE  *fpWrite;

  EXEC SQL BEGIN DECLARE SECTION;

     varchar     v_str_sql[+];    /*SQL语句  */

     varchar     vc_expcol[MAXLEN];

  EXEC SQL END DECLARE SECTION;

  /**/

  strcpy((char *)v_str_sql.arr,sqlname);

  v_str_sql.len=strlen((char*)v_str_sql.arr);

#ifdef   DEBUG

  printf("SQL语句%s.\n",v_str_sql.arr);

#endif

  EXEC SQL WHENEVER SQLERROR GOTO prepare_exp_error;

        if ((fpWrite = fopen(efilename, "w+")) == NULL)

   {

            fprintf(stderr,"Cannot open data file %s\n", efilename);

                  exit();

   }

   /*声明游标处理方式*/

      EXEC SQL PREPARE sqlstmt FROM :v_str_sql;

      EXEC SQL DECLARE extract_cur CURSOR FOR sqlstmt;

      EXEC SQL OPEN extract_cur;

   for(;;)

  {

          /*提取数据*/

      EXEC SQL FETCH extract_cur INTO :vc_expcol ;

      if (sqlca.sqlcode == )

                   {

                       fprintf(stderr,"数据已经抽取完成或是没有符合条件的数据!\n");

                       break;

                    }

                   vc_expcol.arr[vc_expcol.len] = '\0';

                   /*将输出数据记录到文件中*/

       fprintf(fpWrite,"%s\n",vc_expcol.arr );

   }

   /*关闭文件*/

   fclose(fpWrite);

   /*关闭游标*/

   EXEC SQL CLOSE extract_cur;

   return SUCCESS;

prepare_exp_error:

         /*记录错误信息*/

   fprintf(stderr,"\n%70s\n",sqlca.sqlerrm.sqlerrmc);

   fprintf(stderr,"数据库操作错误！退出！");

         return FAILUER;

}