Question

大家好我需要在ORACLE 10g中创建一个触发器，以确保无法输入在birthDate之前的deathDate。我真的很挣钱，请你能提供支持，谢谢亲切的人。

我的计划是：

Actor (actorID, lastName, firstName, middleName, suffix, gender, birthDate, deathDate)
Movie (movieID, title, year, company, totalNoms, awardsWon, DVDPrice, discountPrice)
Quote (quoteID, quote)
Role (roleID ,roleName ,gender ,actorID* ,movieID*) 
RoleQuote (roleID*, quoteID*)

谢谢

如果您需要更多信息，请询问

我的关系约束是：

CONSTRAINT_NAME                C                                                
------------------------------ -                                                
QUOTE_FK                       R                                                
ROLE_FK                        R                                                
MOVIE_ROLE_FK                  R                                                
ACTOR_ROLE_FK                  R                                                
ACTORID                        P                                                
MOVIEID                        P                                                
QUOTEID                        P                                                
ROLEID                         P                                                
ROLEQUOTEID                    P       

Relationships:

ALTER TABLE Role ADD CONSTRAINT ACTOR_ROLE_FK FOREIGN KEY (actorID) REFERENCES Actor (actorID);
ALTER TABLE Role ADD CONSTRAINT MOVIE_ROLE_FK FOREIGN KEY (movieID) REFERENCES Movie (movieID);
ALTER TABLE RoleQuote ADD CONSTRAINT Role_FK FOREIGN KEY (roleID) REFERENCES Role (roleID);
ALTER TABLE RoleQuote ADD CONSTRAINT Quote_FK FOREIGN KEY (quoteID) REFERENCES Quote (quoteID);

Answer 1

这种约束应该实现为CHECK约束

ALTER TABLE actor
  ADD CONSTRAINT chk_birth_before_death CHECK( birthDate < deathDate );

如果您确实需要使用触发器强制执行约束（这将更慢并且需要更多工作）

CREATE OR REPLACE TRIGGER check_death_date
  AFTER INSERT OR UPDATE ON actor
  FOR EACH ROW
BEGIN
  IF( :new.birthDate > :new.deathDate )
  THEN
    RAISE_APPLICATION_ERROR( -20001, 'Birth date cannot be later than death date.' );
  END IF;
END;

协助创建触发器

1 个答案: