问题
向已有表增加字段
执行下面sql，sql执行增加两个字段分别：
- articleTitle 正标题 [nvarchar](200)
- articleSubTitle 副标题 [nvarchar](200)
USE [tg_thirdparty]
GO
/****** Object: Table [dbo].[WX_Activity] Script Date: 10/31/2018 10:54:46 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
IF NOT EXISTS ( SELECT 1
FROM SYSOBJECTS T1
INNER JOIN SYSCOLUMNS T2 ON T1.ID = T2.ID
WHERE T1.NAME = ‘WX_Activity‘
AND T2.NAME = ‘articleTitle‘ )
BEGIN
ALTER TABLE [dbo].[WX_Activity] ADD [articleTitle] [nvarchar](200) NOT NULL
--ALTER TABLE [dbo].[WX_Activity] ADD CONSTRAINT [DF_WX_Activity_articleTitle] DEFAULT (‘‘) FOR [articleTitle]
--ALTER TABLE [dbo].[WX_Activity] ALTER COLUMN [articleTitle] [nvarchar](200) NOT NULL
EXEC sys.sp_addextendedproperty @name = N‘MS_Description‘,
@value = N‘正标题‘, @level0type = N‘SCHEMA‘, @level0name = N‘dbo‘,
@level1type = N‘TABLE‘, @level1name = N‘WX_Activity‘,
@level2type = N‘COLUMN‘, @level2name = N‘articleTitle‘
END
GO
IF NOT EXISTS ( SELECT 1
FROM SYSOBJECTS T1
INNER JOIN SYSCOLUMNS T2 ON T1.ID = T2.ID
WHERE T1.NAME = ‘WX_Activity‘
AND T2.NAME = ‘articleSubTitle‘ )
BEGIN
ALTER TABLE [dbo].[WX_Activity] ADD [articleSubTitle] [nvarchar](200) NOT NULL
--ALTER TABLE [dbo].[WX_Activity] ADD CONSTRAINT [DF_WX_Activity_articleSubTitle] DEFAULT (‘‘) FOR [articleSubTitle]
--ALTER TABLE [dbo].[WX_Activity] ALTER COLUMN [articleSubTitle] [nvarchar](200) NOT NULL
EXEC sys.sp_addextendedproperty @name = N‘MS_Description‘,
@value = N‘副标题‘, @level0type = N‘SCHEMA‘, @level0name = N‘dbo‘,
@level1type = N‘TABLE‘, @level1name = N‘WX_Activity‘,
@level2type = N‘COLUMN‘, @level2name = N‘articleSubTitle‘
END
GO
提示错误
消息 4901，级别 16，状态 1，第 10 行 ALTER TABLE 只允许添加满足下述条件的列: 列可以包含 Null 值；或者列具有指定的 DEFAULT 定义；或者要添加的列是标识列或时间戳列；或者，如果前几个条件均未满足，则表必须为空以允许添加此列。不能将列"articleTitle"添加到非空表"WX_Activity"中，因为它不满足上述条件。 消息 4901，级别 16，状态 1，第 9 行 ALTER TABLE 只允许添加满足下述条件的列: 列可以包含 Null 值；或者列具有指定的 DEFAULT 定义；或者要添加的列是标识列或时间戳列；或者，如果前几个条件均未满足，则表必须为空以允许添加此列。不能将列"articleSubTitle"添加到非空表"WX_Activity"中，因为它不满足上述条件。
解决方法：
表中已经有数据了，不设置默认值，有要求字段不能为NULL，矛盾了！！
所以先指定默认值，插入字段时，加上默认值 DEFAULT ‘‘
USE [tg_thirdparty]
GO
/****** Object: Table [dbo].[WX_Activity] Script Date: 10/31/2018 10:54:46 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
IF NOT EXISTS ( SELECT 1
FROM SYSOBJECTS T1
INNER JOIN SYSCOLUMNS T2 ON T1.ID = T2.ID
WHERE T1.NAME = ‘WX_Activity‘
AND T2.NAME = ‘articleTitle‘ )
BEGIN
ALTER TABLE [dbo].[WX_Activity] ADD [articleTitle] [nvarchar](200) NOT NULL DEFAULT ‘‘
--ALTER TABLE [dbo].[WX_Activity] ADD CONSTRAINT [DF_WX_Activity_articleTitle] DEFAULT (‘‘) FOR [articleTitle]
--ALTER TABLE [dbo].[WX_Activity] ALTER COLUMN [articleTitle] [nvarchar](200) NOT NULL
EXEC sys.sp_addextendedproperty @name = N‘MS_Description‘,
@value = N‘正标题‘, @level0type = N‘SCHEMA‘, @level0name = N‘dbo‘,
@level1type = N‘TABLE‘, @level1name = N‘WX_Activity‘,
@level2type = N‘COLUMN‘, @level2name = N‘articleTitle‘
END
GO
IF NOT EXISTS ( SELECT 1
FROM SYSOBJECTS T1
INNER JOIN SYSCOLUMNS T2 ON T1.ID = T2.ID
WHERE T1.NAME = ‘WX_Activity‘
AND T2.NAME = ‘articleSubTitle‘ )
BEGIN
ALTER TABLE [dbo].[WX_Activity] ADD [articleSubTitle] [nvarchar](200) NOT NULL DEFAULT ‘‘
--ALTER TABLE [dbo].[WX_Activity] ADD CONSTRAINT [DF_WX_Activity_articleSubTitle] DEFAULT (‘‘) FOR [articleSubTitle]
--ALTER TABLE [dbo].[WX_Activity] ALTER COLUMN [articleSubTitle] [nvarchar](200) NOT NULL
EXEC sys.sp_addextendedproperty @name = N‘MS_Description‘,
@value = N‘副标题‘, @level0type = N‘SCHEMA‘, @level0name = N‘dbo‘,
@level1type = N‘TABLE‘, @level1name = N‘WX_Activity‘,
@level2type = N‘COLUMN‘, @level2name = N‘articleSubTitle‘
END
GO
“xxxx”表 - 无法修改表。 不能将值 NULL 插入列 'xxxx'
原文地址：https://www.cnblogs.com/Zev_Fung/p/9882077.html
时间： 2024-08-25 04:32:52