SqlServer2000級聯(lián)刪除的一些問題

字號:

1.建立四個表:
    create table client(
    c_id int identity(1,1),
    c_name nvarchar(255) unique,
    c_pass nvarchar(255),
    c_sex bit,
    c_mail varchar(255),
    c_qq varchar(255),
    primary key(c_id)
    );
    create table album_kind(
    k_id int identity(1,1),
    k_name nvarchar(255),
    k_desc nvarchar(255),
    primary key(k_id)
    );
    create table album(
    a_id int identity(1,1),
    a_name nvarchar(255),
    a_desc nvarchar(255),
    a_create_date datetime,
    a_times bigint,
    c_id int,
    k_id int,
    primary key(a_id),
    foreign key(c_id) references client(c_id) on delete cascade,
    foreign key(k_id) references album_kind(k_id) on delete cascade
    );
    create table album_word(
    aw_id int identity(1,1),
    aw_title nvarchar(255),
    aw_content nvarchar(500),
    commit_date datetime,
    a_id int,
    c_id int,
    primary key(aw_id),
    foreign key(a_id) references album(a_id) on delete cascade,
    foreign key(c_id) references client(c_id) on delete cascade
    );
    這時(創(chuàng)建第四個表的時候)sqlserver2000會報告錯誤:
    將 FOREIGN KEY 約束 'FK_album_word_album' 引入表 'album_word' 中將導(dǎo)致循環(huán)或多重級聯(lián)路徑??荚嚧筇崾菊堉付?ON DELETE NO ACTION 或 ON UPDATE NO ACTION,或修改其它 FOREIGN KEY 約束。[Microsoft][ODBC SQL Server Driver][SQL Server]未能創(chuàng)建約束。請參閱前面的錯誤信息。
    2.這時候我們?nèi)サ舻谒膫€表中的級聯(lián)刪除:
    "on delete cascade"
    再次執(zhí)行。。。。通過
    3.創(chuàng)建一個觸發(fā)器可以解決這個問題(接以上1.2步):
    CREATE TRIGGER album_word_client ON client
    FOR INSERT, UPDATE, DELETE
    AS
    delete album_word from album_word join deleted on album_word.c_id = deleted.c_id
    完成!
    語法:
    create trigger 隨便一個名稱(比如b_a) on 表a
    for delete
    as
    delete 表b from 表b join deleted on 表b.a表外鍵=deleted.a表主鍵
    (當(dāng)刪除a中某條記錄,b中相關(guān)聯(lián)記錄也會相應(yīng)刪除)