--發(fā)現(xiàn)是啟用外鍵約束時(shí)報(bào)的錯(cuò)alter table DM_VOLREV enable constraint VR_VOLID_FK;

1> 先不驗(yàn)證已有數(shù)據(jù)的CONSTRANT,加上參數(shù)NOVALIDATE.*/ALTER TABLE PN_POST ADD CONSTRAINT POST_CLOB_FK FOREIGN KEY (POST_BODY_ID) REFERENCES PN_POST_BODY_CLOB (OBJECT_ID) NOVALIDATE;--2>首先查看兩個(gè)表對(duì)應(yīng)起來(lái)的數(shù)據(jù)有多少select count(*) from dm_volrev t,DM_VOLID k where t.vr_volid = k.vi_volid;--再分別查看單獨(dú)的數(shù)據(jù)，發(fā)現(xiàn)外鍵表多了一行select count(*) from dm_volrev t;select count(*) from DM_VOLID k;-找到多的行并刪除select t.vr_volid from dm_volrev t where t.vr_volid not in (select k.vi_volid from DM_VOLID k);delete from dm_volrev t where t.vr_volid = 479908;--直接重新執(zhí)行啟用外鍵的語(yǔ)句，或者刪除之前的外鍵創(chuàng)建新的外鍵alter table DM_VOLREV drop constraint VR_VOLID_FK;ALTER TABLE DM_VOLREV ADD CONSTRAINT VR_VOLID_FK foreign KEY (VR_VOLID) references DM_VOLID(VI_VOLID) VALIDATE;/*啟用約束:enable( validate) :啟用約束,創(chuàng)建索引,對(duì)已有及新加入的數(shù)據(jù)執(zhí)行約束.enable novalidate :啟用約束,創(chuàng)建索引,僅對(duì)新加入的數(shù)據(jù)強(qiáng)制執(zhí)行約束,而不管表中的現(xiàn)有數(shù)據(jù).禁用約束:disable( novalidate):關(guān)閉約束,刪除索引,可以對(duì)約束列的數(shù)據(jù)進(jìn)行修改等操作.disable validate :關(guān)閉約束,刪除索引,不能對(duì)表進(jìn)行 插入/更新/刪除等操作.*/