Sql 使用主键更改列数据类型
我在80多个不同的表中有一个ReferenceID varchar(6)列。在分配ID的政府组织实施变更后,我需要将其扩展到整个db的varchar(8) 我希望声明一个游标以获得如下表名:Sql 使用主键更改列数据类型,sql,sql-server-2008,primary-key,Sql,Sql Server 2008,Primary Key,我在80多个不同的表中有一个ReferenceID varchar(6)列。在分配ID的政府组织实施变更后,我需要将其扩展到整个db的varchar(8) 我希望声明一个游标以获得如下表名: DECLARE @TableName AS VARCHAR(200) DECLARE TableCursor CURSOR LOCAL READ_ONLY FOR SELECT t.name AS TableName FROM sys.columns c JOIN sys.table
DECLARE @TableName AS VARCHAR(200)
DECLARE TableCursor CURSOR LOCAL READ_ONLY FOR
SELECT t.name AS TableName
FROM sys.columns c
JOIN sys.tables t ON c.object_id = t.object_id
WHERE c.name = 'ReferenceID'
OPEN TableCursor
FETCH NEXT FROM TableCursor
INTO @TableName
ALTER TABLE @TableName ALTER COLUMN ReferenceID VARCHAR(8)
然后按如下方式编辑类型:
DECLARE @TableName AS VARCHAR(200)
DECLARE TableCursor CURSOR LOCAL READ_ONLY FOR
SELECT t.name AS TableName
FROM sys.columns c
JOIN sys.tables t ON c.object_id = t.object_id
WHERE c.name = 'ReferenceID'
OPEN TableCursor
FETCH NEXT FROM TableCursor
INTO @TableName
ALTER TABLE @TableName ALTER COLUMN ReferenceID VARCHAR(8)
这会失败,因为该列是某些表中主键的一部分(PK中包含的列因表而异)
我真的不想为每个表手动删除和重新创建每个PK
在游标中,有没有一种方法可以在更改数据类型之前禁用PK,然后重新启用它,或者在更改数据类型的任意一侧删除并重新创建PK,请记住,PK将取决于我们当前正在查看的表?您需要将
ALTER
语句作为动态SQL执行:将该语句构建为SQL字符串,并将其传递给sp_executesql
您需要在ALTER表中显式指定NOT NULL
。。。更改列
,否则默认为允许NULL
。PK列中不允许这样做
下面的操作很好
CREATE TABLE p
(
ReferenceID VARCHAR(6) NOT NULL PRIMARY KEY
)
INSERT INTO p VALUES ('AAAAAA')
ALTER TABLE p ALTER COLUMN ReferenceID VARCHAR(8) NOT NULL
当省略notnull
时,会出现以下错误
Msg 5074, Level 16, State 1, Line 1
The object 'PK__p__E1A99A792180FB33' is dependent on column 'ReferenceID'.
Msg 4922, Level 16, State 9, Line 1
ALTER TABLE ALTER COLUMN ReferenceID failed because one or more objects access this column.
<> P>在编程方法中要考虑的两件事是,您需要暂时删除引用“代码”>引用ID 列的任何外键,并且确保(不包含“<代码> > NULL < /代码>”(非PK)。
ReferenceID
当前可为空的列。编辑如果您的数据库混乱不堪,并且由于长达10年的开发(政府政策的变化足以导致“良好的数据库设计”)而混合使用varchar(6)和char(6)列,则需要此解决方案最终崩溃。)
结束编辑
对于那些说我必须放弃并重新创建PK的人,你是对的。索引和外键也需要删除和重新创建
幸运的是,索引和FK的数量是可以管理的,所以我将它们作为“例外”处理,并在脚本开始时一次删除一个,然后在脚本结束时一次重新添加一个(请参见下面的/**/中的两个部分)
然后,SQL脚本的主体将有关FK的完整细节提示到临时表中,然后循环遍历每个表名,删除FK,更改数据类型,重新添加FK
组装好的SQL字符串打印在下面的脚本中。如果你打算重复使用(没有提供任何保证,等等,诸如此类),请将其注释掉,以使执行时间减少50%
SET NOCOUNT ON
/* Handle exceptional tables here
* Remove indexes and foreign keys
* --Lots of "IF EXISTS ... ALTER TABLE <name> DROP CONSTRAINT <constraint name>, etc.
*/
--Declare variables
DECLARE @SQL VARCHAR(8000)
DECLARE @TableName VARCHAR(512)
DECLARE @ConstraintName VARCHAR(512)
DECLARE @tColumn VARCHAR(512)
DECLARE @Columns VARCHAR(8000)
DECLARE @IsDescending BIT
--Set up temporary table
SELECT
tbl.[schema_id],
tbl.name AS TableName,
i.NAME AS IndexName,
i.type_desc,
c.[column],
c.key_ordinal,
c.is_desc,
i.[object_id],
s.no_recompute,
i.[ignore_dup_key],
i.[allow_row_locks],
i.[allow_page_locks],
i.[fill_factor],
dsi.type,
dsi.name AS DataSpaceName
INTO #PKBackup
FROM
sys.tables AS tbl
INNER JOIN sys.indexes AS i
ON (
i.index_id > 0
AND i.is_hypothetical = 0
)
AND ( i.[object_id] = tbl.[object_id] )
INNER JOIN (
SELECT
ic.[object_id] ,
c.[name] [column] ,
ic.is_descending_key [is_desc],
ic.key_ordinal
FROM
sys.index_columns ic
INNER JOIN
sys.indexes i
ON
i.[object_id] = ic.[object_id]
AND
i.index_id = 1
AND
ic.index_id = 1
INNER JOIN
sys.tables t
ON
t.[object_id] = ic.[object_id]
INNER JOIN
sys.columns c
ON
c.[object_id] = t.[object_id]
AND
c.column_id = ic.column_id
) AS c
ON c.[object_id] = i.[object_id]
LEFT OUTER JOIN
sys.key_constraints AS k
ON
k.parent_object_id = i.[object_id]
AND
k.unique_index_id = i.index_id
LEFT OUTER JOIN
sys.data_spaces AS dsi
ON
dsi.data_space_id = i.data_space_id
LEFT OUTER JOIN
sys.xml_indexes AS xi
ON
xi.[object_id] = i.[object_id]
AND
xi.index_id = i.index_id
LEFT OUTER JOIN
sys.stats AS s
ON
s.stats_id = i.index_id
AND
s.[object_id] = i.[object_id]
WHERE
k.TYPE = 'PK'
DECLARE TableCursor CURSOR LOCAL READ_ONLY FOR
SELECT t.name AS TableName
FROM sys.columns c
JOIN sys.tables t ON c.object_id = t.object_id
WHERE
c.name = 'ReferenceID'
OPEN TableCursor
FETCH NEXT FROM TableCursor
INTO @TableName
WHILE @@FETCH_STATUS = 0
BEGIN
PRINT('--Updating ' + @TableName + '...')
SELECT @ConstraintName = PK.CONSTRAINT_NAME
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK
WHERE
PK.TABLE_NAME = @TableName
AND
PK.CONSTRAINT_TYPE = 'PRIMARY KEY'
--drop the constraint
--Some tables don't have a PK defined, only do the next bit if they do
IF (SELECT COUNT(*) FROM #PKBackup PK WHERE PK.TableName = @TableName) > 0
BEGIN
SET @SQL = 'ALTER TABLE @TableName DROP CONSTRAINT @ConstraintName'
SET @SQL = REPLACE(@SQL, '@TableName', @TableName)
SET @SQL = REPLACE(@SQL, '@ConstraintName', @ConstraintName)
PRINT @SQL
EXEC (@SQL)
END
--This is where we actually change the datatype of the column
SET @SQL = 'ALTER TABLE @TableName ALTER COLUMN ReferenceID VARCHAR(8)' + (SELECT CASE WHEN C.Is_Nullable = 'NO' THEN ' NOT NULL' ELSE '' END
FROM INFORMATION_SCHEMA.COLUMNS C
WHERE C.TABLE_NAME = @TableName AND C.COLUMN_NAME = 'ReferenceID')
SET @SQL = REPLACE(@SQL, '@TableName', @TableName)
PRINT(@SQL)
EXEC(@SQL)
--Recreate the constraint
--Some tables don't have a PK defined, only do the next bit if they do
IF (SELECT COUNT(*) FROM #PKBackup PK WHERE PK.TableName = @TableName) > 0
BEGIN
--First set up @SQL template
SELECT @SQL = 'ALTER TABLE [' + SCHEMA_NAME(PK.schema_id) + '].[' + PK.TableName
+ '] ADD CONSTRAINT [' + PK.IndexName
+ '] PRIMARY KEY ' + Type_desc + ' ( @Columns ) WITH '
+ '( PAD_INDEX = ' + CASE WHEN CAST(INDEXPROPERTY(pk.[object_id], PK.IndexName, N'IsPadIndex') AS BIT) = 0 THEN 'OFF'
ELSE 'ON'
END + ', '
+ 'STATISTICS_NORECOMPUTE = ' + CASE WHEN pk.no_recompute = 0 THEN 'OFF'
ELSE 'ON'
END
+ ', SORT_IN_TEMPDB = OFF, '
+ 'IGNORE_DUP_KEY = ' + CASE WHEN pk.[ignore_dup_key] = 0 THEN 'OFF'
ELSE 'ON'
END + ', '
+ 'ONLINE = OFF, '
+ 'ALLOW_ROW_LOCKS = ' + CASE WHEN pk.allow_row_locks = 0 THEN 'OFF'
ELSE 'ON'
END + ', '
+ 'ALLOW_PAGE_LOCKS = ' + CASE WHEN pk.allow_page_locks = 0 THEN 'OFF'
ELSE 'ON'
END + ', '
+ 'FILLFACTOR = ' + CASE WHEN pk.[fill_factor] = 0 THEN '100'
ELSE CONVERT(NVARCHAR, pk.[fill_factor])
END + ' '
+ ') ON [' + CASE WHEN 'FG' = pk.[type] THEN pk.DataSpaceName
ELSE N''
END + ']'
FROM
#PKBackup PK WHERE PK.TableName = @TableName
SET @SQL = REPLACE(@SQL, '@TableName', @TableName)
SET @SQL = REPLACE(@SQL, '@ConstraintName', @ConstraintName)
--Second, build up @Columns
SET @Columns = ' '
DECLARE ColumnCursor CURSOR LOCAL READ_ONLY FOR
SELECT pk.[column], PK.is_desc
FROM #PKBackup PK
WHERE PK.TableName = @TableName
ORDER BY PK.key_ordinal ASC
OPEN ColumnCursor
FETCH NEXT FROM ColumnCursor
INTO @tColumn, @IsDescending
WHILE @@FETCH_STATUS = 0
BEGIN
SET @Columns = @Columns + @tColumn + CASE WHEN @IsDescending = 1 THEN ' DESC, ' ELSE ' ASC, ' END
--Get the next TableName
FETCH NEXT FROM ColumnCursor
INTO @tColumn, @IsDescending
END
--Tidy up
CLOSE ColumnCursor
DEALLOCATE ColumnCursor
--Delete the last comma
SET @Columns = LEFT(@Columns, LEN(@Columns) - 1)
END
--Recreate the constraint
SET @SQL = REPLACE(@SQL, '@Columns', @Columns)
PRINT @SQL
EXEC (@SQL)
PRINT('--Done
')
SET @SQL = ''
--Get the next TableName
FETCH NEXT FROM TableCursor
INTO @TableName
END
--Tidy up
CLOSE TableCursor
DEALLOCATE TableCursor
DROP TABLE #PKBackup
/* Handle exceptional tables here
* Replace indexes and foreign keys that were removed at the start
*/
SET NOCOUNT OFF
将NOCOUNT设置为ON
/*在这里处理特殊的表格
*删除索引和外键
*--大量“如果存在……更改表删除约束等”。
*/
--声明变量
声明@SQL VARCHAR(8000)
声明@TableName VARCHAR(512)
声明@ConstraintName VARCHAR(512)
声明@tColumn VARCHAR(512)
声明@Columns VARCHAR(8000)
声明@IsDescending位
--设置临时表
挑选
tbl.[schema_id],
tbl.name作为表名,
i、 名称为IndexName,
i、 类型_desc,
c、 [专栏],
c、 关键点(序数),
c、 是_desc,
i、 [对象id],
s、 没有重新计算,
i、 [忽略重复键],
i、 [允许行锁定],
i、 [允许页面锁定],
i、 [填充系数],
dsi.type,
dsi.name作为DataSpaceName
进入#PKBackup
从…起
sys.tables作为tbl
内部连接sys.index作为i
在(
i、 索引id>0
i.is_=0
)
和(i.[object\u id]=tbl.[object\u id])
内连接(
挑选
ic.[对象id],
c、 [姓名][栏目],
ic.is_下降键[is_下降],
ic.key_序数
从…起
sys.index_列ic
内连接
系统索引i
在…上
i、 [object\u id]=ic.[object\u id]
及
i、 索引id=1
及
ic.index_id=1
内连接
系统表t
在…上
t、 [object\u id]=ic.[object\u id]
内连接
sys.c列
在…上
c、 [object\u id]=t.[object\u id]
及
c、 column\u id=ic.column\u id
)AS c
在c.[object\u id]=i.[object\u id]上
左外连接
sys.key_约束为k
在…上
k、 父对象id=i.[对象id]
及
k、 唯一索引id=i.index\U id
左外连接
sys.data_空间作为dsi
在…上
dsi.data\u space\u id=i.data\u space\u id
左外连接
席
在…上
席[物]
及
X.NoxxIdID.I.索引XIDID
左外连接
sys.stats为s
在…上
s、 stats\u id=i.index\u id
及
s、 [object\u id]=i.[object\u id]
哪里
k、 类型='PK'
将TableCursor游标声明为本地只读
选择t.name作为TableName
来自sys.c列
在c.object\u id=t.object\u id上连接sys.tables t
哪里
c、 名称='ReferenceID'
打开表格光标
从TableCursor获取下一个
转换为@TableName
而@@FETCH\u STATUS=0
开始
打印('--更新'+@TableName+'…'))
选择@ConstraintName=PK.CONSTRAINT\u NAME
从…起
信息\u SCHEMA.TABLE\u约束PK
哪里
PK.TABLE_NAME=@TableName
及
PK.CONSTRAINT_TYPE='主键'
--放弃约束
--有些表没有定义PK,只有定义PK时才执行下一位
如果(从#PKBackup PK中选择COUNT(*),其中PK.TableName=@TableName)>0
开始
SET@SQL='ALTER TABLE@TableName DROP CONSTRAINT@ConstraintName'
设置@SQL=REPLACE(@SQ