SQL 更新期间违反 UNIQUE KEY 约束

Question

我有一个简单的数据库表（SQL Server 2008 R2 Express），其定义如下：

ID         INT          Auto Inc, PK
Name       VARCHAR(64)  Unique Key
Telephone  VARCHAR(128)

我有一个存储过程，我执行它来更新表中的记录，它基本上执行以下操作：

UPDATE customers
SET    Name = @name, Telephone = @Telephone
WHERE  id = @id

目前，我在表格中有两个条目

ID   Name    Telephone
1    Fred    01234 567890
2    John    09876 543210

当我调用我的存储过程来更新 John 的电话号码时，有效执行的 SQL 是

UPDATE customers
SET    Name = 'John', Telephone = '02468 135790'
WHERE  id = 2

这会在 Name 字段上生成 UNIQUE KEY 冲突。现在由于 Name 字段实际上并没有改变，为什么会发生这种情况？

由于我的应用程序使用存储过程处理所有数据库操作，我可以通过删除约束并修改存储过程以手动强制执行约束来解决此问题，但这似乎是错误的。

鉴于我的表实际上有更多字段，我必须有一个通用的解决方法来防止这些错误约束问题，而不必生成大量存储过程来更新特定字段？

编辑：上表经过简化以使问题更易于管理，我很确定我没有遗漏任何重要内容，但对于信息，该表的实际定义如下

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[companies](
    [id] [int] IDENTITY(1,1) NOT NULL,
    [typeId] [int] NOT NULL,
    [name] [varchar](64) NOT NULL,
    [displayName] [varchar](128) NOT NULL,
    [deliveryAddress] [varchar](1024) NOT NULL,
    [invoiceAddress] [varchar](1024) NOT NULL,
    [telephone] [varchar](64) NOT NULL,
    [fax] [varchar](64) NOT NULL,
    [email] [varchar](256) NOT NULL,
    [website] [varchar](256) NULL,
    [isActive] [bit] NOT NULL,
 CONSTRAINT [PK_companies] PRIMARY KEY CLUSTERED 
(
    [id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY],
 CONSTRAINT [Unique Display Name] UNIQUE NONCLUSTERED 
(
    [displayName] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY],
 CONSTRAINT [Unique Name] UNIQUE NONCLUSTERED 
(
    [name] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[companies]  WITH CHECK ADD  CONSTRAINT [Company Type] FOREIGN KEY([id])
REFERENCES [dbo].[companyTypes] ([id])
GO

ALTER TABLE [dbo].[companies] CHECK CONSTRAINT [Company Type]
GO

...和存储过程

ALTER PROCEDURE UpdateCompany

    @id                 INT,
    @typeId             INT,
    @name               VARCHAR(64),
    @displayName        VARCHAR(128),
    @deliveryAddress    VARCHAR(1024),
    @invoiceAddress     VARCHAR(1024),
    @telephone          VARCHAR(64),
    @fax                VARCHAR(64),
    @email              VARCHAR(256),
    @website            VARCHAR(256),
    @isActive           BIT

AS
BEGIN

    UPDATE  companies
    SET     typeid = @typeid,
            name = @name,
            displayname = @displayname,
            deliveryAddress = @deliveryAddress,
            invoiceAddress = @invoiceAddress,
            telephone = @telephone,
            fax = @fax,
            email = @email,
            website = @website,
            isActive = @isActive

    EXEC    GetCompany @id


END
GO

Answer 1

您的UPDATE 语句中缺少WHERE，因此目前它会尝试使用相同的值更新表中的所有行。