您指定了两次表名。ALTER TABLE部分为表命名。 试一试: 修改表TableName alter column [Date] default gettcdate

修改表TableName drop constraint DF_TableName_WhenEntered

修改表TableName 添加约束DF_TableName_WhenEntered 默认的getutcdate()为WhenEntered

您指定了两次表名。ALTER TABLE部分为表命名。 试一试: 修改表TableName alter column [Date] default gettcdate

我使用下面的存储过程来更新列上的默认值。

在添加新的默认值之前，它会自动删除列上之前的任何默认值。

用法示例:

-- Update default to be a date.
exec [dbo].[AlterDefaultForColumn] '[dbo].[TableName]','Column','getdate()';
-- Update default to be a number.
exec [dbo].[AlterDefaultForColumn] '[dbo].[TableName]','Column,'6';
-- Update default to be a string. Note extra quotes, as this is not a function.
exec [dbo].[AlterDefaultForColumn] '[dbo].[TableName]','Column','''MyString''';

存储过程:

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

-- Sample function calls:
--exec [dbo].[AlterDefaultForColumn] '[dbo].[TableName]','ColumnName','getdate()';
--exec [dbol].[AlterDefaultForColumn] '[dbo].[TableName]','Column,'6';
--exec [dbo].[AlterDefaultForColumn] '[dbo].[TableName]','Column','''MyString''';
create PROCEDURE [dbo].[ColumnDefaultUpdate]
    (
        -- Table name, including schema, e.g. '[dbo].[TableName]'
        @TABLE_NAME VARCHAR(100), 
        -- Column name, e.g. 'ColumnName'.
        @COLUMN_NAME VARCHAR(100),
        -- New default, e.g. '''MyDefault''' or 'getdate()'
        -- Note that if you want to set it to a string constant, the contents
        -- must be surrounded by extra quotes, e.g. '''MyConstant''' not 'MyConstant'
        @NEW_DEFAULT VARCHAR(100)
    )
AS 
BEGIN       
    -- Trim angle brackets so things work even if they are included.
    set @COLUMN_NAME = REPLACE(@COLUMN_NAME, '[', '')
    set @COLUMN_NAME = REPLACE(@COLUMN_NAME, ']', '')

    print 'Table name: ' + @TABLE_NAME;
    print 'Column name: ' + @COLUMN_NAME;
    DECLARE @ObjectName NVARCHAR(100)
    SELECT @ObjectName = OBJECT_NAME([default_object_id]) FROM SYS.COLUMNS
    WHERE [object_id] = OBJECT_ID(@TABLE_NAME) AND [name] = @COLUMN_NAME;

    IF @ObjectName <> '' 
    begin
        print 'Removed default: ' + @ObjectName;
        --print('ALTER TABLE ' + @TABLE_NAME + ' DROP CONSTRAINT ' + @ObjectName)
        EXEC('ALTER TABLE ' + @TABLE_NAME + ' DROP CONSTRAINT ' + @ObjectName)
    end

    EXEC('ALTER TABLE ' + @TABLE_NAME + ' ADD  DEFAULT (' + @NEW_DEFAULT + ') FOR ' + @COLUMN_NAME)
    --print('ALTER TABLE ' + @TABLE_NAME + ' ADD  DEFAULT (' + @NEW_DEFAULT + ') FOR ' + @COLUMN_NAME)
    print 'Added default of: ' + @NEW_DEFAULT;
END

此存储过程消除的错误

如果你试图在一个已经存在的列中添加一个默认值，你会得到以下错误(如果使用这个存储的proc，你永远不会看到):

-- Using the stored procedure eliminates this error:
Msg 1781, Level 16, State 1, Line 1
Column already has a DEFAULT bound to it.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.

我确认像JohnH的评论一样，永远不要在你的对象名称中使用列类型! 这是令人困惑的。尽可能使用括号。

试试这个:

ALTER TABLE [TableName]
ADD  DEFAULT (getutcdate()) FOR [Date]; 

你可以用方括号括起保留字来避免这些错误:

dbo.TableName.[Date]