我需要将一个表的主键更改为一个标识列,并且在表中已经有许多行。
我有一个脚本来清理id,以确保它们从1开始是顺序的,在我的测试数据库上运行良好。
更改列以具有标识属性的SQL命令是什么?
我需要将一个表的主键更改为一个标识列,并且在表中已经有许多行。
我有一个脚本来清理id,以确保它们从1开始是顺序的,在我的测试数据库上运行良好。
更改列以具有标识属性的SQL命令是什么?
当前回答
这里有一个很酷的解决方案: 在列上添加或删除标识属性
简而言之,在SQL管理器中手动编辑您的表,切换标识,不要保存更改,只显示将为更改创建的脚本,复制它并稍后使用。
这节省了大量的时间,因为它(脚本)包含了所有与您更改的表相关的外键、索引等。手动写这个…上帝保佑。
其他回答
您不能更改现有列的标识。
你有两个选择,
创建一个带有标识的新表并删除现有表 创建一个具有标识的新列并删除现有列
方法1。(新表)在这里,您可以保留新创建的标识列上的现有数据值。请注意,如果不满足'if not exists',您将丢失所有数据,因此请确保您将条件也放在drop上!
CREATE TABLE dbo.Tmp_Names
(
Id int NOT NULL
IDENTITY(1, 1),
Name varchar(50) NULL
)
ON [PRIMARY]
go
SET IDENTITY_INSERT dbo.Tmp_Names ON
go
IF EXISTS ( SELECT *
FROM dbo.Names )
INSERT INTO dbo.Tmp_Names ( Id, Name )
SELECT Id,
Name
FROM dbo.Names TABLOCKX
go
SET IDENTITY_INSERT dbo.Tmp_Names OFF
go
DROP TABLE dbo.Names
go
Exec sp_rename 'Tmp_Names', 'Names'
方法2(新列)不能在新创建的标识列上保留现有数据值,标识列将保留数字序列。
Alter Table Names
Add Id_new Int Identity(1, 1)
Go
Alter Table Names Drop Column ID
Go
Exec sp_rename 'Names.Id_new', 'ID', 'Column'
请参阅以下Microsoft SQL Server论坛帖子了解更多细节:
如何将列更改为identity(1,1)
As I understood in normal cases we are creating a table with Primary key which is having Identity property So Rename or Delete a column which is associated with Primary Key constraint will not be possible because constraint Rules are validating column structure. Tto achieve this we have to process some steps in the following way: Let us assume TableName = 'Employee' and ColumnName = 'EmployeeId' 1. Add new column 'EmployeeId_new' in the 'Employee' table ALTER TABLE Employee ADD EmployeeId_new INT IDENTITY(1,1)
Now remove column 'EmployeeId' from 'Employee' table ALTER TABLE Employee DROP COLUMN EmployeeId This will throw error because of Primary Key Constraint rules are applicable and validating column structure. *### 'Msg 5074, Level 16, State 1, Line 1 The object [PK_dbo.Employee] is dependent on colmn [EmployeeId].'### So we have to remove the Primary Key constraint first from the table 'Employee' then we can remove the column ALTER TABLE Employee DROP constraint [PK_dbo.Employee] Now we can remove the column 'EmployeeId' from 'Employee' table as did in the previous step where we got error ALTER TABLE Employee DROP COLUMN EmployeeId Now Column 'EmployeeId' removed from table So we will Rename the newly added new column 'EmployeeId_new' with 'EmployeeId' sp_rename 'Employee.EmployeeId', 'EmployeeId_new', 'COLUMN' To rearrange the table in the same form as It was, we have to add Primary Key Constraint for the column 'EmployeeId' ALTER TABLE Employee add constraint [PK_dbo.Employee] primary key (EmployeeId)
8. 现在,带有'EmployeeId'的表'Employee'随着现有的主键约束被修改为Identity规则
为所有没有标识集的主键= bigint的表生成脚本;这将返回每个表的生成脚本列表;
SET NOCOUNT ON;
declare @sql table(s varchar(max), id int identity)
DECLARE @table_name nvarchar(max),
@table_schema nvarchar(max);
DECLARE vendor_cursor CURSOR FOR
SELECT
t.name, s.name
FROM sys.schemas AS s
INNER JOIN sys.tables AS t
ON s.[schema_id] = t.[schema_id]
WHERE EXISTS (
SELECT
[c].[name]
from sys.columns [c]
join sys.types [y] on [y].system_type_id = [c].system_type_id
where [c].[object_id] = [t].[object_id] and [y].name = 'bigint' and [c].[column_id] = 1
) and NOT EXISTS
(
SELECT 1 FROM sys.identity_columns
WHERE [object_id] = t.[object_id]
) and exists (
select 1 from sys.indexes as [i]
inner join sys.index_columns as [ic] ON i.OBJECT_ID = ic.OBJECT_ID AND i.index_id = ic.index_id
where object_name([ic].[object_id]) = [t].[name]
)
OPEN vendor_cursor
FETCH NEXT FROM vendor_cursor
INTO @table_name, @table_schema
WHILE @@FETCH_STATUS = 0
BEGIN
DELETE FROM @sql
declare @pkname varchar(100),
@pkcol nvarchar(100)
SELECT top 1
@pkname = i.name,
@pkcol = COL_NAME(ic.OBJECT_ID,ic.column_id)
FROM sys.indexes AS [i]
INNER JOIN sys.index_columns AS [ic] ON i.OBJECT_ID = ic.OBJECT_ID AND i.index_id = ic.index_id
WHERE i.is_primary_key = 1 and OBJECT_NAME(ic.OBJECT_ID) = @table_name
declare @q nvarchar(max) = 'SELECT '+@pkcol+' FROM ['+@table_schema+'].['+@table_name+'] ORDER BY '+@pkcol+' DESC'
DECLARE @ident_seed nvarchar(max) -- Change this to the datatype that you are after
SET @q = REPLACE(@q, 'SELECT', 'SELECT TOP 1 @output = ')
EXEC sp_executeSql @q, N'@output bigint OUTPUT', @ident_seed OUTPUT
insert into @sql(s) values ('BEGIN TRANSACTION')
insert into @sql(s) values ('BEGIN TRY')
-- create statement
insert into @sql(s) values ('create table ['+@table_schema+'].[' + @table_name + '_Temp] (')
-- column list
insert into @sql(s)
select
' ['+[c].[name]+'] ' +
y.name +
(case when [y].[name] like '%varchar' then
coalesce('('+(case when ([c].[max_length] < 0 or [c].[max_length] >= 1024) then 'max' else cast([c].max_length as varchar) end)+')','')
else '' end)
+ ' ' +
case when [c].name = @pkcol then 'IDENTITY(' +COALESCE(@ident_seed, '1')+',1)' else '' end + ' ' +
( case when c.is_nullable = 0 then 'NOT ' else '' end ) + 'NULL ' +
coalesce('DEFAULT ('+(
REPLACE(
REPLACE(
LTrim(
RTrim(
REPLACE(
REPLACE(
REPLACE(
REPLACE(
LTrim(
RTrim(
REPLACE(
REPLACE(
object_definition([c].default_object_id)
,' ','~')
,')',' ')
)
)
,' ','*')
,'~',' ')
,' ','~')
,'(',' ')
)
)
,' ','*')
,'~',' ')
) +
case when object_definition([c].default_object_id) like '%get%date%' then '()' else '' end
+
')','') + ','
from sys.columns c
JOIN sys.types y ON y.system_type_id = c.system_type_id
where OBJECT_NAME(c.[object_id]) = @table_name and [y].name != 'sysname'
order by [c].column_id
update @sql set s=left(s,len(s)-1) where id=@@identity
-- closing bracket
insert into @sql(s) values( ')' )
insert into @sql(s) values( 'SET IDENTITY_INSERT ['+@table_schema+'].['+@table_name+'_Temp] ON')
declare @cols nvarchar(max)
SELECT @cols = STUFF(
(
select ',['+c.name+']'
from sys.columns c
JOIN sys.types y ON y.system_type_id = c.system_type_id
where c.[object_id] = OBJECT_ID(@table_name)
and [y].name != 'sysname'
and [y].name != 'timestamp'
order by [c].column_id
FOR XML PATH ('')
)
, 1, 1, '')
insert into @sql(s) values( 'IF EXISTS(SELECT * FROM ['+@table_schema+'].['+@table_name+'])')
insert into @sql(s) values( 'EXEC(''INSERT INTO ['+@table_schema+'].['+@table_name+'_Temp] ('+@cols+')')
insert into @sql(s) values( 'SELECT '+@cols+' FROM ['+@table_schema+'].['+@table_name+']'')')
insert into @sql(s) values( 'SET IDENTITY_INSERT ['+@table_schema+'].['+@table_name+'_Temp] OFF')
insert into @sql(s) values( 'DROP TABLE ['+@table_schema+'].['+@table_name+']')
insert into @sql(s) values( 'EXECUTE sp_rename N''['+@table_schema+'].['+@table_name+'_Temp]'', N'''+@table_name+''', ''OBJECT''')
if ( @pkname is not null ) begin
insert into @sql(s) values('ALTER TABLE ['+@table_schema+'].['+@table_name+'] ADD CONSTRAINT ['+@pkname+'] PRIMARY KEY CLUSTERED (')
insert into @sql(s)
select ' ['+COLUMN_NAME+'] ASC,' from information_schema.key_column_usage
where constraint_name = @pkname
GROUP BY COLUMN_NAME, ordinal_position
order by ordinal_position
-- remove trailing comma
update @sql set s=left(s,len(s)-1) where id=@@identity
insert into @sql(s) values (' )')
end
insert into @sql(s) values ('--Run your Statements')
insert into @sql(s) values ('COMMIT TRANSACTION')
insert into @sql(s) values ('END TRY')
insert into @sql(s) values ('BEGIN CATCH')
insert into @sql(s) values (' ROLLBACK TRANSACTION')
insert into @sql(s) values (' DECLARE @Msg NVARCHAR(MAX) ')
insert into @sql(s) values (' SELECT @Msg=ERROR_MESSAGE() ')
insert into @sql(s) values (' RAISERROR(''Error Occured: %s'', 20, 101,@msg) WITH LOG')
insert into @sql(s) values ('END CATCH')
declare @fqry nvarchar(max)
-- result!
SELECT @fqry = (select char(10) + s from @sql order by id FOR XML PATH (''))
SELECT @table_name as [Table_Name], @fqry as [Generated_Query]
PRINT 'Table: '+@table_name
EXEC sp_executeSql @fqry
FETCH NEXT FROM vendor_cursor
INTO @table_name, @table_schema
END
CLOSE vendor_cursor;
DEALLOCATE vendor_cursor;
在对象资源管理器中右键单击表名。你会得到一些选择。点击“设计”。将为该表打开一个新选项卡。您可以在“列属性”中添加标识约束。
基本上有四个逻辑步骤。
创建一个新的Identity列。为这个新列打开Insert Identity。 将源列(希望转换为Identity的列)中的数据插入到这个新列中。 关闭新列的Insert Identity。 删除源列并将新列重命名为源列的名称。
可能会有一些更复杂的事情,比如跨多个服务器工作等。
有关步骤(使用ssms和T-sql),请参阅下面的文章。这些步骤适用于不太熟悉T-SQL的初学者。
http://social.technet.microsoft.com/wiki/contents/articles/23816.how-to-convert-int-column-to-identity-in-the-ms-sql-server.aspx