在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，我执行以更新表中的记录，基本上执行以下操作：

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

目前，我在表中有两个条目

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违规。 现在，由于Name字段实际上没有变化，为什么会出现这种情况？

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

鉴于我的表实际上有更多的字段，我必须有一个通用的工作来防止这些错误的约束问题，而不必生成大量的存储过程来更新特定的字段？

编辑 ：上面的表格被简化以保持问题更易于管理，我很确定我没有错过任何重要的内容，但是对于信息，表格的实际定义如下

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

您在UPDATE语句中缺少WHERE ，因此它目前将尝试使用相同的值更新表中的所有行。