Question

创建表格语句：

CREATE TABLE Client(
    nclient INT NOT NULL, 
    nom VARCHAR(45) NOT NULL UNIQUE,
    plafond NUMERIC(10,2) DEFAULT 0,
    CHECK (plafond>=0),
    CONSTRAINT PK_Client PRIMARY KEY (nclient)
  );

CREATE TABLE Compte( 
    ncompte INT NOT NULL, 
    solde NUMERIC(10,2),
    ouvert NUMERIC(1) DEFAULT 1,
    nbessais INT,
    code Numeric(4),
    nclient NUMERIC(4),
    CONSTRAINT PK_Compte PRIMARY KEY (ncompte),
    CONSTRAINT FK_Compte_nclient_Client FOREIGN KEY (nclient) REFERENCES Client(nclient),
    CONSTRAINT CK_solde CHECK (solde>=0),
    CONSTRAINT CK_ouvert CHECK(ouvert between 0 and 1),
    CONSTRAINT CK_code CHECK (code>0)
  );

CREATE TABLE Operation( 
    noperation INT NOT NULL, 
    dateoperation DATE Default SYSDATE,
    codepropose NUMERIC(4),
    montant NUMERIC(10,2),
    ncompte INT,
    CONSTRAINT PK_Operation PRIMARY KEY (noperation),
    CONSTRAINT FK_Ope_ncompte_Compte FOREIGN KEY (ncompte) REFERENCES Compte(ncompte),
    CONSTRAINT CK_codepropose CHECK (codepropose>=0),
    CONSTRAINT CK_montant CHECK (montant>=0)
  );

CREATE TABLE Historique(
    nhistorique INT NOT NULL, 
    dateoperation DATE DEFAULT SYSDATE,
    montant NUMERIC(10,2),
    ncompte INT,
    CONSTRAINT PK_Historique PRIMARY KEY (nhistorique)
  );

CREATE TABLE Incident(
    nincident INT NOT NULL, 
    message VARCHAR(45),
    noperation INT,
    CONSTRAINT PK_Incident PRIMARY KEY (nincident),
    CONSTRAINT FK_Inc_noperation_Operation FOREIGN KEY (noperation) REFERENCES Operation(noperation)
  );

触发代码：

create or replace TRIGGER TRG_OPERATION_CARTE
  AFTER INSERT OR UPDATE ON Operation
  FOR EACH ROW
  DECLARE
    solde NUMBER := 0;
    ouvert NUMBER := 0;
    essai NUMBER := 0;
    code NUMBER := 0;
    plafondActuel NUMBER := 0;
    decouvertAuth NUMBER := 0;
  BEGIN
    SELECT SUM(montant) INTO plafondActuel FROM Operation WHERE dateoperation >= SYSDATE - 7 AND ncompte = :NEW.ncompte;
    SELECT plafond INTO decouvertAuth FROM Client Cl LEFT JOIN Compte Cp ON Cl.nclient = Cp.nclient WHERE Cp.ncompte = :NEW.ncompte;
    SELECT solde, ouvert, nbessais, code
      INTO solde, ouvert, essai, code
      FROM Compte
      WHERE Compte.ncompte = :NEW.ncompte;    
    IF ouvert = 0 THEN
      INSERT INTO Incident (message,noperation) values ('Compte bloqué',:NEW.noperation);
    ELSE
      IF :NEW.codepropose = code THEN
        IF (solde + decouvertAuth) > :NEW.montant THEN
          IF (plafondActuel + :NEW.montant) > 300 THEN
            INSERT INTO Incident (message,noperation) values ('Lopération dépasse le plafond authorisé',:NEW.noperation);
          ELSE
            INSERT INTO Historique (montant,ncompte) values (:NEW.montant,:NEW.ncompte);
          END IF;
        ELSE
          INSERT INTO Incident (message,noperation) values ('Lopération dépasse le découvert authorisé',:NEW.noperation);
        END IF;
      ELSE
        essai := essai + 1;
        UPDATE Compte SET nbessais = essai WHERE Compte.ncompte = :NEW.ncompte;
        IF essai >=3 THEN
          UPDATE Compte SET ouvert = 0 WHERE Compte.ncompte = :NEW.ncompte;
          INSERT INTO Incident (message,noperation) values ('Compte bloqué, 3 tentatives échouées',:NEW.noperation);
        END IF;
      END IF;
    END IF;
  END;

我很确定算法和触发器是正确的，但我有一个错误：

原因：触发器（或此语句中引用的用户定义的plsql函数）尝试查看（或修改）正在被触发它的语句修改的表。

操作：重写触发器（或函数），使其不读取该表。

以下是一些测试，除最后一次插入外，一切正常：

INSERT INTO Client (nom) values ('abderrahmane');
INSERT INTO Client (nom) values ('ben');
Select * FROM Client;
INSERT INTO Compte (solde,nclient) values (200,1);
INSERT INTO Compte (nclient,code) values (2,2403);
INSERT INTO Compte (solde,nclient) values (2300,3);
SELECT * FROM Compte;
INSERT INTO Operation (montant,ncompte) values (200,2);
INSERT INTO Operation (codepropose,ncompte) values (2010,2);
INSERT INTO Operation (ncompte) values (1);
INSERT INTO Operation (codepropose,montant,ncompte) values (2020,20,1);
INSERT INTO Operation (codepropose,montant,ncompte,dateoperation) values (2030,30,2,'01/01/2001');
INSERT INTO Operation (codepropose,montant,ncompte) values (2030,30,3);
SELECT * FROM Operation;  
INSERT INTO Historique (montant,ncompte) values (200,2);
INSERT INTO Historique (dateoperation,ncompte) values ('15/04/16',2);
INSERT INTO Historique (ncompte) values (1);
INSERT INTO Historique (dateoperation,montant,ncompte) values ('15/04/16',20,1);
INSERT INTO Historique (dateoperation,montant,ncompte) values ('15/04/16',30,3);
SELECT * FROM Historique;
INSERT INTO Incident (message,noperation) values ('Incident 1',2);
INSERT INTO Incident (message,noperation) values ('Incident 2',8);
INSERT INTO Incident (message,noperation) values ('Incident 3',1);
SELECT * FROM Incident; 
UPDATE Compte SET ouvert = 0 WHERE nclient = 2;
INSERT INTO Operation (montant,ncompte,codepropose) values (200,2,2403);
SELECT * FROM Incident;

Answer 1

Mutating Table错误的出现是因为您正在使用该特定表并在同一个表中进行任何类型的修改。由于您尝试在同一个表的触发器中从表中选择记录，因此会出现此错误。

Answer 2

感谢大家的答案，我只需要更改表名，而不是从操作中获取总和，我从历史中获取它：

CREATE OR REPLACE TRIGGER TRG_OPERATION_CARTE
  AFTER INSERT OR UPDATE ON Operation
  FOR EACH ROW
  DECLARE
    solde NUMBER := 0;
    ouvert NUMBER := 0;
    essai NUMBER := 0;
    code NUMBER := 0;
    plafondActuel NUMBER := 0;
    decouvertAuth NUMBER := 0;
  BEGIN
    SELECT SUM(montant) INTO plafondActuel FROM Historique WHERE dateoperation >= SYSDATE - 7 AND ncompte = :NEW.ncompte;
    SELECT plafond INTO decouvertAuth FROM Client Cl LEFT JOIN Compte Cp ON Cl.nclient = Cp.nclient WHERE Cp.ncompte = :NEW.ncompte;
    SELECT solde, ouvert, nbessais, code
      INTO solde, ouvert, essai, code
      FROM Compte
      WHERE Compte.ncompte = :NEW.ncompte;    
    IF ouvert = 0 THEN
      INSERT INTO Incident (message,noperation) values ('Compte bloqué',:NEW.noperation);
    ELSE
      IF :NEW.codepropose = code THEN
        IF (solde + decouvertAuth) >= :NEW.montant THEN
          IF (plafondActuel + :NEW.montant) > 300 THEN
            INSERT INTO Incident (message,noperation) values ('Lopération dépasse le plafond authorisé',:NEW.noperation);
          ELSE
            UPDATE Compte SET solde = (solde - :NEW.montant) WHERE Compte.ncompte = :NEW.ncompte;
            INSERT INTO Historique (montant,ncompte) values (:NEW.montant,:NEW.ncompte);
          END IF;
        ELSE
          INSERT INTO Incident (message,noperation) values ('Lopération dépasse le découvert authorisé',:NEW.noperation);
        END IF;
      ELSE
        essai := essai + 1;
        UPDATE Compte SET nbessais = essai WHERE Compte.ncompte = :NEW.ncompte;
        IF essai >=3 THEN
          UPDATE Compte SET ouvert = 0 WHERE Compte.ncompte = :NEW.ncompte;
          INSERT INTO Incident (message,noperation) values (CONCAT('Compte bloqué : tentative n° ', essai),:NEW.noperation); 
        ELSE
          INSERT INTO Incident (message,noperation) values (CONCAT('Code erroné : tentative n° ', essai),:NEW.noperation); 
        END IF;
      END IF;
    END IF;
  END;
/

插入触发器后导致变异表错误

2 个答案: