Sql server SQL Server：指向一个表的两个外键。错误：引入外键约束可能导致循环或多个级联路径

我得到了一个错误：

味精1785，第16级，状态0，第238行
在表“Studios”上引入外键约束“FK_Studios_Members_HeadId”可能会导致循环或多个级联路径。指定“在删除时不执行操作”或“在更新时不执行操作”，或修改其他外键约束

下面是我遇到问题的两个表的简化版本：

CREATE TABLE [Members] 
(
    [MemberId] int NOT NULL IDENTITY
)

CREATE TABLE [Studios] 
(
    [StudioId] int NOT NULL IDENTITY,
    [HeadId] int,
    [OwnerId] int,

    CONSTRAINT [PK_Studios] PRIMARY KEY ([StudioId]),

    CONSTRAINT [FK_Studios_Members_OwnerId] 
         FOREIGN KEY ([OwnerId]) REFERENCES [Members] ([MemberId]) 
            ON DELETE SET NULL,
    CONSTRAINT [FK_Studios_Members_HeadId] 
         FOREIGN KEY ([HeadId]) REFERENCES [Members] ([MemberId]) 
            ON DELETE SET NULL
)

我发现如果我切换两个FK的顺序，第二个FK总是会出错。我不明白为什么这会导致级联问题，因为两者都有“ON DELETE SET NULL”

这是由EF核心代码首先生成的，所以我需要这些关系，不能只是在后端破解触发器

---

我遗漏了什么？

我不确定答案是否适用于您的设计，我也不确定您的设计是如何确定的……但作为替代设计，我认为不会有相同的问题，您是否考虑过单独的中间关系表

这种方法的一个好处是，它允许您在每个位置拥有多个成员

CREATE TABLE [Members] 
(
    [MemberId] int NOT NULL IDENTITY
)

CREATE TABLE [Studios] 
(
    [StudioId] int NOT NULL IDENTITY,

    CONSTRAINT [PK_Studios] PRIMARY KEY ([StudioId]),

)

--Contains Owner, Head, etc.
CREATE TABLE [Relationships] 
(
    [RelationshipId] int NOT NULL IDENTITY,
    [RelationshipId] nvarchar(20) NOT NULL
)

CREATE TABLE [StudioMemberRelationships]
(
    [StudioMemberRelationshipId] int NOT NULL IDENTITY,
    [StudioId] int NOT NULL,
    [MemberId] int NOT NULL,
    [RelationshipTypeId] int NOT NULL,

    CONSTRAINT [FK_StudioMemberRelationships_StudioId] 
         FOREIGN KEY ([StudioId]) REFERENCES [Studios] ([StudioId]) 
            ON DELETE SET NULL,
    CONSTRAINT [FK_StudioMemberRelationships_MemberId] 
         FOREIGN KEY ([MemberId]) REFERENCES [Members] ([MemberId]) 
            ON DELETE SET NULL,
    CONSTRAINT [FK_StudioMemberRelationships_RelationshipId] 
         FOREIGN KEY ([RelationshipId]) REFERENCES [Relationships] ([RelationshipId]) 
            ON DELETE SET NULL
)

---

我不确定是否有一个答案能与你的答案相匹配，我也不确定你的设计是如何固定的……但作为一个替代设计，我认为不会有同样的问题，你考虑过一个单独的中间关系表吗

这种方法的一个好处是，它允许您在每个位置拥有多个成员

CREATE TABLE [Members] 
(
    [MemberId] int NOT NULL IDENTITY
)

CREATE TABLE [Studios] 
(
    [StudioId] int NOT NULL IDENTITY,

    CONSTRAINT [PK_Studios] PRIMARY KEY ([StudioId]),

)

--Contains Owner, Head, etc.
CREATE TABLE [Relationships] 
(
    [RelationshipId] int NOT NULL IDENTITY,
    [RelationshipId] nvarchar(20) NOT NULL
)

CREATE TABLE [StudioMemberRelationships]
(
    [StudioMemberRelationshipId] int NOT NULL IDENTITY,
    [StudioId] int NOT NULL,
    [MemberId] int NOT NULL,
    [RelationshipTypeId] int NOT NULL,

    CONSTRAINT [FK_StudioMemberRelationships_StudioId] 
         FOREIGN KEY ([StudioId]) REFERENCES [Studios] ([StudioId]) 
            ON DELETE SET NULL,
    CONSTRAINT [FK_StudioMemberRelationships_MemberId] 
         FOREIGN KEY ([MemberId]) REFERENCES [Members] ([MemberId]) 
            ON DELETE SET NULL,
    CONSTRAINT [FK_StudioMemberRelationships_RelationshipId] 
         FOREIGN KEY ([RelationshipId]) REFERENCES [Relationships] ([RelationshipId]) 
            ON DELETE SET NULL
)

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你看到了吗？我不知道这是否有助于回答这个问题，但它帮助我理解了一般问题：-）嗯，许多可能的重复之一：你看到了吗？我不知道这是否有助于回答这个问题，但它帮助我理解了一般问题：-）嗯，许多可能的重复之一：