PL/SQL 找不到数据异常处理

Question

我有一个 EMAILS 表，其中包含以下列：ROUTINE、EMAILS 和 COPIES，它们定义了应该使用 UTL_MAIL 将特定过程的结果发送给谁（至/cc）。

我有以下代码：

PROCEDURE myproc AS
  NO_EMAIL_FOUND EXCEPTION;
  e EMAILS%ROWTYPE;
  x NUMBER;
BEGIN

  --fetch data
  SELECT x INTO x FROM <...>;

  --fetch emails
  SELECT * INTO e FROM emails WHERE routine='FRS_WEEKLY';
  IF e.emails IS NULL AND e.copies IS NULL THEN
    RAISE NO_EMAIL_FOUND;
  END IF;

  <send mail code using UTL_MAIL>;

  EXCEPTION
    WHEN NO_EMAIL_FOUND THEN <code1>;
    WHEN NO_DATA_FOUND THEN <code2>;
    WHEN OTHERS THEN NULL; --RAISE;

END myproc;

我希望 myproc 在 EMAILS 表中没有电子邮件时执行 code1。我的问题是没有引发 NO_EMAIL_FOUND 异常并且 code2 执行，因为在 SELECT 语句中引发了 NO_DATA_FOUND 异常。如何避免这种情况？

Answer 1

试试这个：

PROCEDURE myproc AS
    NO_EMAIL_FOUND EXCEPTION;
    e EMAILS%ROWTYPE;
    x NUMBER;
BEGIN

    BEGIN
        --fetch data
        SELECT x INTO x FROM <...>;

        --fetch emails
        BEGIN
            SELECT * INTO e FROM emails WHERE routine='FRS_WEEKLY';
        EXCEPTION WHEN NO_DATA_FOUND THEN
            RAISE NO_EMAIL_FOUND;
        END;
        IF e.emails IS NULL AND e.copies IS NULL THEN
            RAISE NO_EMAIL_FOUND;
        END IF;

        <send mail code using UTL_MAIL>;

    EXCEPTION
        WHEN NO_EMAIL_FOUND THEN <code1>;
        WHEN NO_DATA_FOUND THEN <code2>;
        WHEN OTHERS THEN NULL; --RAISE;
    END;

END myproc;

Answer 2

使用这个：

PROCEDURE myproc AS
  NO_EMAIL_FOUND EXCEPTION;
  e EMAILS%ROWTYPE;
  x NUMBER;
BEGIN

  --fetch data
  SELECT x INTO x FROM <...>;

  --fetch emails
  BEGIN
    SELECT * INTO e FROM emails WHERE routine='FRS_WEEKLY';
  EXCEPTION
    WHEN NO_DATA_FOUND THEN
      RAISE NO_EMAIL_FOUND;
  END;

  IF e.emails IS NULL AND e.copies IS NULL THEN
    RAISE NO_EMAIL_FOUND;
  END IF;

  <send mail code using UTL_MAIL>;

  EXCEPTION
    WHEN NO_EMAIL_FOUND THEN <code1>;
    WHEN NO_DATA_FOUND THEN <code2>;
    WHEN OTHERS THEN NULL; --RAISE;

END myproc;

我希望您知道此例程只能处理一封电子邮件；如果有多个，则会引发 TOO_MANY_ROWS 异常。