sql - SQL删除触发器在

Question

假设我有三个表：

表格1：

 ID     INT     PRIMARY
 name NVARCHAR

表_2：

ID         INT    PRIMARY
Table_1_ID INT (foreign key)

表3：

ID         INT    PRIMARY
Table_2_ID INT (foreign key)

前两个表具有以下触发器：

-- Table_1
CREATE TRIGGER tr_1
ON Table_1
INSTEAD OF DELETE
AS
BEGIN
    DELETE FROM Table_2
    WHERE Table_1_ID IN (SELECT deleted.ID FROM Table_1)

    DELETE FROM Table_1
    WHERE ID IN (SELECT deleted.ID FROM deleted)
END

-- Table_2
CREATE TRIGGER sr_bf_trigger_delete_ID
ON Table_2
INSTEAD OF DELETE
AS
BEGIN
    DELETE FROM Table_3
    WHERE Table_2_ID IN (SELECT deleted.ID FROM deleted)

    DELETE FROM Table_2
    WHERE ID IN (SELECT deleted.ID FROM deleted)
END

这个想法是，一旦我删除了 中的一行（或多行）Table_1，它将启动触发器并删除 中的相应行Table_2。但是，在删除 中的行之前，会删除 中的Table_2相应行Table_3。

这行得通吗？我看到的可能问题是我两次访问同一个“已删除”表。

Answer 1

您的触发器将在较小的更正下正常工作（删除错别字）：

CREATE TRIGGER tr_1
ON Table_1
INSTEAD OF DELETE
AS
BEGIN
    DELETE FROM Table_2
    WHERE Table_1_ID IN (SELECT d.ID FROM deleted as d)

    DELETE FROM Table_1
    WHERE ID IN (SELECT d.ID FROM deleted as d)
END;

-- Table_2
CREATE TRIGGER sr_bf_trigger_delete_ID
ON Table_2
INSTEAD OF DELETE
AS
BEGIN
    DELETE FROM Table_3
    WHERE Table_2_ID IN (SELECT d.ID FROM deleted as d)

    DELETE FROM Table_2
    WHERE ID IN (SELECT d.ID FROM deleted as d)
END;

看sql fiddle demo