.Net Core EF不允许我输入相同的外键

Question

我有一个带有外键的模型。 .NET Core EF如何使我无法两次向该表输入相同的外键。

public class DolsMcaClientModel
{
    [Key]
    public int DolsMcaClientID { get; set; }

    public int DolsMcaItemID { get; set; }
    public virtual DolsMcaItemModel DolsMcaItemModel  { get; set; }

    public int ClientID { get; set; }

    [Required]
    public int FileID { get; set; }
    public virtual FileModel FileModel { get; set; }
}

在此表中， DolsMcaClientID 是我的身份列，而 DolsMcaItemID 是我的外部列。 DolsMcaItemModel 是我的导航属性。

我无法为不同的客户端输入相同的DolsMcaItemID。 DolsMcaItemID充当表中的主键。但事实并非如此。

ERROR: System.Data.SqlClient.SqlException: Cannot insert duplicate key row in object 'dbo.DolsMcaClientModels' with unique index 'IX_DolsMcaClientModels_DolsMcaItemID'. The duplicate key value is (1).

如果我从表中删除DolsMcaItemID 1项目，那么我可以使用DolsMcaItemId 1将新条目添加到表中，但是对于任何clientID只能添加一次...对于其他任何clientID，我都无法输入DolsMcaItem 1

我的SQL表创建查询是：

CREATE TABLE [dbo].[DolsMcaClientModels](
[DolsMcaClientID] [int] IDENTITY(1,1) NOT NULL,
[DolsMcaItemID] [int] NOT NULL,
[ClientID] [int] NOT NULL,
[FileID] [int] NOT NULL,
 CONSTRAINT [PK_DolsMcaClientModels] PRIMARY KEY CLUSTERED 
(
    [DolsMcaClientID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

ALTER TABLE [dbo].[DolsMcaClientModels]  WITH CHECK ADD  CONSTRAINT [FK_DolsMcaClientModels_DolsMcaItemModels_DolsMcaItemID] FOREIGN KEY([DolsMcaItemID])
REFERENCES [dbo].[DolsMcaItemModels] ([DolsMcaItemID])
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[DolsMcaClientModels] CHECK CONSTRAINT [FK_DolsMcaClientModels_DolsMcaItemModels_DolsMcaItemID]
GO

ALTER TABLE [dbo].[DolsMcaClientModels]  WITH CHECK ADD  CONSTRAINT [FK_DolsMcaClientModels_FileModels_FileID] FOREIGN KEY([FileID])
REFERENCES [dbo].[FileModels] ([FileID])
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[DolsMcaClientModels] CHECK CONSTRAINT [FK_DolsMcaClientModels_FileModels_FileID]
GO

Answer 1

该列上的UNIQUE索引 [IX_DolsMcaClientModels_DolsMcaItemID] 阻止您提交具有相同 [DolsMcaItemID] 的另一条记录。

修正是删除唯一索引：

ALTER TABLE [dbo].[DolsMcaClientModels] DROP INDEX [IX_DolsMcaClientModels_DolsMcaItemID];

CREATE INDEX [IX_DolsMcaClientModels_DolsMcaItemID] ON [dbo].[DolsMcaClientModels] ([DolsMcaItemID])

别忘了搭建数据库上下文，以从代码中删除约束。