- SQL code
--创建学生表create table student( stuid int primary key , --主键，想设置为自增长 sname varchar(10), sex number(1), birthday date );-- 建立序列： create sequence stu_sequence minvalue 1 maxvalue 99999999999999999999999999 start with 1 increment by 1 cache 20;-- 建立触发器，写法1 CREATE OR REPLACE TRIGGER "stu_trigger" BEFORE INSERT ON student FOR EACH ROW declare next_checkup_no number; begin select stu_sequence.nextval into next_checkup_no from dual; :NEW.stuid := next_checkup_no; end;-- 建立触发器，写法2create or replace trigger "stu_trigger" before insert on student for each row begin select stu_sequence.nextval into :new.stuid from dual; end;--插入数据1insert into student values(1,'riyun',0,sysdate);--插入数据2insert into student values('tom',0,sysdate);问题：1、建立触发器的写法1和2有什么不同？
2、:NEW.stuid := next_checkup_no这里的“：”代表什么意思？
3、当执行插入数据1的时候oracle报“该触发器无效且未通过重新验证”错误？
4、当执行插入数据2的时候oracle报“没有足够的值”错误？
请大侠们帮忙看下指点迷津！！3q
------解决方案--------------------
1.写法不同而已，1中有局部变量，2中没有
2.:new中的:是一个整体，指新增的行，:=是指对变是赋值，也是一个整体
3.这个说明建立的触发器有问题
4.你的表有四列而你只入了三列,至少应是，这样列才匹配，但能不能执行是另一回事
insert into student(sname,sex,birthday) values('tom',0,sysdate);
------解决方案--------------------
CREATE OR REPLACE TRIGGER "TRI_DATAID" BEFORE INSERT ON "TIGER"."WEB_DATA" REFERENCING OLD AS "OLD" NEW AS "NEW" FOR EACH ROW
DECLARE last_Sequence NUMBER; last_InsertID NUMBER; factor NUMBER; BEGIN IF (:NEW."DATAID" IS NULL) THEN SELECT "DATA_0".NEXTVAL INTO :NEW."DATAID" FROM DUAL; ELSE SELECT Last_Number-1 INTO last_Sequence FROM User_Sequences WHERE UPPER(Sequence_Name) = UPPER('DATA_0'); SELECT :NEW."DATAID" INTO last_InsertID FROM DUAL; WHILE (last_InsertID > last_Sequence) LOOP SELECT "DATA_0".NEXTVAL INTO last_Sequence FROM DUAL; END LOOP; END IF; END;