“xxxx”表 - 無法修改表。 不能將值 NULL 插入列 'xxxx'

問題

向已有表增加字段

執行下面sql，sql執行增加兩個字段分別：

1. articleTitle 正標題 [nvarchar](200)
2. articleSubTitle 副標題 [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'正標題', @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'副標題', @level0type = N'SCHEMA', @level0name = N'dbo',
            @level1type = N'TABLE', @level1name = N'WX_Activity',
            @level2type = N'COLUMN', @level2name = N'articleSubTitle'


    END
    
GO
    

 

提示錯誤

消息 4901，級別 16，狀態 1，第 10 行
ALTER TABLE 只允許添加滿足下述條件的列: 列可以包含 Null 值；或者列具有指定的 DEFAULT 定義；或者要添加的列是標識列或時間戳列；或者，如果前幾個條件均未滿足，則表必須為空以允許添加此列。不能將列"articleTitle"添加到非空表"WX_Activity"中，因為它不滿足上述條件。
消息 4901，級別 16，狀態 1，第 9 行
ALTER TABLE 只允許添加滿足下述條件的列: 列可以包含 Null 值；或者列具有指定的 DEFAULT 定義；或者要添加的列是標識列或時間戳列；或者，如果前幾個條件均未滿足，則表必須為空以允許添加此列。不能將列"articleSubTitle"添加到非空表"WX_Activity"中，因為它不滿足上述條件。

 

 

解決方法：

表中已經有數據了，不設置默認值，有要求字段不能為NULL，矛盾了！！

所以先指定默認值，插入字段時，加上默認值 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'正標題', @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'副標題', @level0type = N'SCHEMA', @level0name = N'dbo',
            @level1type = N'TABLE', @level1name = N'WX_Activity',
            @level2type = N'COLUMN', @level2name = N'articleSubTitle'


    END
    
GO