如果同一天批准了多笔交易，如何避免员工进行交易？

【问题标题】：how to avoid a transaction for the employee if more than one transaction is approved on same day?如果同一天批准了多笔交易，如何避免员工进行交易？
【发布时间】：2015-12-08 13:23:05
【问题描述】：

如果同一天批准了多笔交易，如何避免员工的交易？请尽快帮助我。

【问题讨论】：

有一个唯一的约束？

标签： sql plsql

【解决方案1】：

-- To check in the anonymous block code if CONSTRAINT cannot be applied later on the table

    DECLARE
      lv_cnt PLS_INTEGER;
      lv_emp PLS_INTEGER;
      lv_day DATE;
    BEGIN
      SELECT COUNT(1)
      INTO lv_cnt
      FROM emp
      WHERE empno          = lv_emp
      AND transaction_stat = 'APPROVED'
      AND tran_date        = lv_day;
      IF lv_cnt            > 1 THEN
        RAISE_APPLICATION_ERROR(-200001,'Cannot proceed with this transaction as already approved transaction for this day is present',TRUE);
      ELSE
        dbms_output.put_line('your piece of code for new transaction');
      END IF;
    END;

【讨论】：