Question

我有桌子：团队和比赛。

'Teams'存储有关足球队的信息，而我特别感兴趣的是国家队。

'匹配'存储“团队”中列出的球队之间发生的足球比赛信息。我从这张桌子感兴趣的领域是竞赛领域。根据比赛的类型：“全英格兰”或“全西班牙”等，所涉及的球队应来自相应的国家。

我目前正在尝试编写一个Constraint Trigger来处理这个问题但是，即使编译好了，SQL Developer也会在运行时抛出一个非常神秘的错误“无效且失败的重新验证”。有人在乎帮忙吗？以更好的方式做事的建议也很棒。下面的PL / SQL块，如果下面的代码让你们中的任何一个哭，我道歉。我知道我这很糟糕

CREATE OR REPLACE TRIGGER matchcountry_BIR
BEFORE INSERT ON matches
FOR EACH ROW

DECLARE
invalidEng EXCEPTION;
invalidSpa EXCEPTION;
team1 teams.Country%type;
team2 teams.Country%type;
comp matches.Competition%type;

BEGIN
SELECT Country INTO team1 FROM teams WHERE TeamID = :new.TeamID_A;
SELECT Country INTO team2 FROM teams WHERE TeamID = :new.TeamID_B;
comp:=:new.Competition;

IF (comp='All England') AND (team1!='England' AND team2!='England') THEN
RAISE invalidEng;
END IF;

IF (comp='All Spain') AND (team1!='Spain' AND team2!='Spain') THEN
RAISE invalidSpa;
END IF;

EXCEPTION
WHEN invalidEng THEN
RAISE_APPLICATION_ERROR(-20005, 'Countries are invalid for a English competition.');
END;

EXCEPTION
WHEN invalidSpa THEN
RAISE_APPLICATION_ERROR(-20006, 'Countries are invalid for a Spanish competition.');
END;

如果表格存在问题，我还会包含他们的Create语句。同样，对这些建议或批评也非常欢迎。

CREATE TABLE teams
(
  TeamID number(2) PRIMARY KEY,
  TeamName varchar2(50),
  Country varchar2(30),
  CHECK (Country='Spain' OR Country='England')
);

CREATE TABLE matches
(
  MatchID number(2) PRIMARY KEY,
  TeamID_A number(2),
  TeamID_B number(2),
  Goal_A number(2),
  Goal_B number(2),
  Competition varchar2(50),
  CONSTRAINT fk_TeamA FOREIGN KEY(TeamID_A) REFERENCES teams,
  CONSTRAINT fk_TeamB FOREIGN KEY(TeamID_B) REFERENCES teams,
  CHECK (Goal_A >= 0),
  CHECK (Goal_B >= 0),
  CHECK (Competition='Champions League' OR Competition='Europa League' OR Competition='All England' OR Competition='All Spain')
);

Answer 1

你有3个错误：

&&代替AND。
访问matches表而不是:new.competition。
加倍EXCEPTION关键字。

尝试以下代码：

-- Trigger will not let an insert on the Match table with invalid countries for the competition
CREATE OR REPLACE TRIGGER matchcountry_BIR
BEFORE INSERT ON matches
FOR EACH ROW

DECLARE
  invalidEng EXCEPTION;
  invalidSpa EXCEPTION;
  team1 teams.Country%type;
  team2 teams.Country%type;
  comp matches.Competition%type;

BEGIN
  SELECT Country INTO team1 FROM teams WHERE TeamID = :new.TeamID_A;
  SELECT Country INTO team2 FROM teams WHERE TeamID = :new.TeamID_B;
  --SELECT Competition INTO comp FROM matches WHERE MatchID = :new.MatchID;
  comp := :new.competition;

  IF (comp='All England') AND (team1!='England' AND team2!='England') THEN
    RAISE invalidEng;
  END IF;

  IF (comp='All Spain') AND (team1!='Spain' AND team2!='Spain') THEN
    RAISE invalidSpa;
  END IF;

EXCEPTION
  WHEN invalidEng THEN
    RAISE_APPLICATION_ERROR(-20005, 'Countries are invalid for a English competition.');

  WHEN invalidSpa THEN
    RAISE_APPLICATION_ERROR(-20006, 'Countries are invalid for a Spanish competition.');
END;

Oracle PL / SQL约束触发器

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