動態SQL小結

服務器的連接：

//connect to local database 連接服務器 szUsrId爲用戶名 szUsrPwd爲密碼 con_local 連接代名詞 szSrv爲數據源結構爲如 192.168.1.1;9000 ip加端口
exec sql CONNECT :szUsrId IDENTIFIED BY :szUsrPwd at :con_local using :szSrv;

exec sql CONNECT :szUsrId2 IDENTIFIED BY :szUsrPwd2 at :con_remote using :szSrv2;

exec sql set close on endtran off;

exec sql disconnect all;

SQL操作（sql循環遊標提取數據事例）

// 說明SQL變量

  exec sql begin declare section;
       CS_CHAR task_id[2048];
       CS_INT task_ref_id;
      CS_INT task_status;
   exec sql end declare section;

   memset(szSQLString,0,sizeof(szSQLString));
   sprintf(szSQLString,"select task_id,task_ref_id,task_status from aex_int_task where task_status = 3",szModule);
   exec sql at :con_local prepare mod_pre from :szSQLString;/*準備SQL語句*/// 用PREPARE語句分析當前的動態sql語句，語句名是mod_pre

   exec sql at :con_local declare mod_cursor cursor for mod_pre;//申明遊標mod_pre的遊標名爲mod_cursor
   if(Check_Error(szSQLString,__LINE__,__FILE__)==1)
   {
        exec sql rollback;
        return -1;
   }
    exec sql at :con_local open mod_cursor; //打開遊標
    if(Check_Error(szSQLString,__LINE__,__FILE__)==1)
   {
        exec sql rollback;
       return -1;
   }
   exec sql at :con_local fetch mod_cursor into :task_id,:task_ref_id, :task_status;//從遊標中提取SQL所執行的數據
    while(sqlca.sqlcode == 0)//循環執行遊標循環提取數據
   {
         //數組處理存放在內存數據空間
        strcpy(aex_int_task_List[aex_int_task_ListCount].task_id,task_id);
        aex_int_task_List[aex_int_task_ListCount].task_ref_id=task_ref_id;
        aex_int_task_List[aex_int_task_ListCount].task_status=task_status;
       WriteLog(__LINE__,"task_ref_id=%d,task_status=%d\n",task_ref_id,task_status);
      aex_int_task_ListCount++;
         exec sql at :con_local fetch mod_cursor into :task_id,:task_ref_id, :task_status;
    }
    exec sql at :con_local close mod_cursor;/*關閉遊標*/
    exec sql at :con_local deallocate cursor mod_cursor;/*銷燬遊標*/

SQL操作（sql提取數據事例）

     memset(szSQLString,0,sizeof(szSQLString));
     sprintf(szSQLString,"select isnull(sum(case result_flag when 1 then 1 else 0 end),0) as sccuess, isnull(sum(case result_flag when 2 then 1 else 0 end),0) as fail       from pub_cmd_result where log_code='%s' and result_module='aex'",str_task_id);
     exec sql at :con_remote prepare count_flag_pre from :szSQLString;
     if(Check_Error(szSQLString,__LINE__,__FILE__)==1)
     {
       exec sql at :con_remote rollback;
       return -1;
     }
     exec sql at :con_remote execute count_flag_pre into :successSQL,:failSQL;//獲取成功數和失敗數

exec sql at :con_remote commit;//提交事務

SQL操作（sql獲取數據參數事例）

// 說明SQL變量
EXEC SQL BEGIN DECLARE SECTION;
      char* username=USERNAME;
      char* password=PASSWORD;
      VARCHAR sqlstmt[80];
      int emp_number;
      VARCHAR emp_name[15];
      VARCHAR job[50],job1[50],job2[50];
      float salary;
EXEC SQL END DECLARE SECTION;
    //EXEC SQL CONNECT :username IDENTIFIED BY :password;
    // 構造動態SQL語句
    sqlstmt.len=sprintf(sqlstmt.arr,"INSERT INTO EMP(EMPNO,ENAME,JOB,SAL)VALUES(:V1,:V2,:V3,:V4)");
    // 用PREPARE語句分析當前的動態INSERT語句，語句名是S
    EXEC SQL PREPARE S FROM :sqlstmt;
    // 循環插表
    for(;;)
    {
        printf("/nEnter employee number:");    scanf("%d",&emp_number);
        printf("/nEnter employee name:");   scanf("%s",&emp_name.arr);
        emp_name.len=strlen(emp_name.arr);
        printf("/nEnter employee job:");     scanf("%s",&job.arr);     job.len=strlen(job.arr);
        salary = 0; // With VC6, Missing this line will cause C Run-Time Error R6002.
        printf("/nEnter salary:");     scanf("%f",&salary);
        EXEC SQL EXECUTE S USING :emp_number,:emp_name,:job,:salary;   //獲取參數
    }