[英]Change a Primary Key from Nonclustered to Clustered
假设我有一个 SQL Server 2005 表 TableX,上面有 2 个索引:
PK_TableX = FieldA 上的主键非聚集
IX_TableX_FieldB = 在 FieldB 上聚集
我想将 PK 切换为 CLUSTERED,将另一个索引切换为 NONCLUSTERED。
我必须假设在我尝试更改索引回合时数据库将被使用 - 所以我想避免的主要问题是在过程中的某个时刻表上将不存在 PK 约束。 我希望免受插入重复密钥的任何风险。
即我不能只是删除主键并重新创建它。
此过程需要通过 SQL 脚本完成,而不是通过 SSMS。
我有一种我认为可行的方法(我将其作为潜在答案发布),但我想打开它,以防万一我遗漏了某些东西或有另一种/更好的方法。 另外,它可能在未来对其他人有用
1)先删除现有的聚集索引(IX_TableX_FieldB):
DROP INDEX TableX.IX_TableX_FieldB
2)对主键中引用的唯一字段创建(临时)UNIQUE约束
ALTER TABLE TableX
ADD CONSTRAINT UQ_TableX UNIQUE(FieldA)
3) 删除主键
ALTER TABLE TableX
DROP CONSTRAINT PK_TableX
4) 将 PRIMARY KEY 重新创建为 CLUSTERED
ALTER TABLE TableX
ADD CONSTRAINT PK_TableX PRIMARY KEY CLUSTERED(FieldA)
5) 删除临时 UNIQUE 约束
ALTER TABLE TableX
DROP CONSTRAINT UQ_TableX
6) 将 IX_TableX_FieldB 添加为 NONCLUSTERED
CREATE NONCLUSTERED INDEX IX_TableX_FieldB ON TableX(FieldB)
我知道这很旧,但这将编写所有 FK 掉落、pk 掉落、pk 重新创建、FK 重新创建的脚本。 将 MYTABLE 替换为您的表名。
IF EXISTS (SELECT * FROM sys.tables WHERE object_id = OBJECT_ID(N'[dbo].[FKAgainstTableList]'))
BEGIN
DROP TABLE FKAgainstTableList
END
--CREATE TABLE FKAgainstTableList (ForeignKey VARCHAR(30),[Table] VARCHAR(30))
DECLARE @PKTableName VARCHAR(100),
@PKName varchar(100),
@FKName varchar(100),
@sql varchar(max),
@PKcolumnName varchar(30),
@table VARCHAR(100),
@FKColumnName VARCHAR(100),
@parentColumnNumber int
SET @PKTableName = 'MYTABLE'
set @PKName = (SELECT name FROM sys.indexes WHERE OBJECT_NAME(object_id) = @PKTableName AND is_primary_key = 1)
set @PKcolumnName = (SELECT name FROM sys.columns WHERE OBJECT_NAME(object_id) = @PKTableName AND is_identity =1)
PRINT @PKcolumnName
SELECT OBJECT_NAME(sys.foreign_key_columns.parent_object_id) [Table],sys.columns.name [FKColumnName],sys.foreign_keys.name [FKName]
INTO FKAgainstTableList
FROM sys.foreign_keys INNER JOIN sys.foreign_key_columns
ON sys.foreign_keys.object_id = sys.foreign_key_columns.constraint_object_id
INNER JOIN sys.columns ON sys.columns.object_id = sys.foreign_keys.parent_object_id AND sys.columns.column_id = sys.foreign_key_columns.parent_column_id
WHERE OBJECT_NAME(sys.foreign_keys.referenced_object_id) = @PKTableName
DECLARE table_cur1 CURSOR FOR
SELECT * FROM FKAgainstTableList
PRINT @sql
-------------------------------Disable constraint on FK Tables
OPEN table_cur1
FETCH NEXT FROM table_cur1 INTO @table,@FKColumnName,@FKName
WHILE @@FETCH_STATUS = 0
BEGIN
SET @sql ='ALTER TABLE '+@table+' DROP CONSTRAINT '+ @FKName
PRINT @sql
FETCH NEXT FROM table_cur1 INTO @table,@FKColumnName,@FKName
END
CLOSE table_cur1
DEALLOCATE table_cur1
--------------------------------DROP AND recreate CLUSTERED pk
IF EXISTS (SELECT 1 FROM sys.indexes WHERE object_id = OBJECT_ID(@PKTableName) AND name = @PKName)
BEGIN
SET @sql = 'ALTER TABLE '+@PKTableName+' DROP CONSTRAINT '+ @PKName
PRINT @sql
END
SET @sql = 'ALTER TABLE '+@PKTableName +' ADD CONSTRAINT '+@PKName+' PRIMARY KEY CLUSTERED ('+@PKcolumnName+' ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY]'
PRINT(@sql)
--------------------------------Enable FK constraints on FK tables.
DECLARE table_cur2 CURSOR FOR
SELECT * FROM FKAgainstTableList
OPEN table_cur2
FETCH NEXT FROM table_cur2 INTO @table,@FKColumnName,@FKName
WHILE @@FETCH_STATUS = 0
BEGIN
SET @sql = 'ALTER TABLE '+@table+' WITH NOCHECK ADD CONSTRAINT '+ @FKName+' FOREIGN KEY(['+@FKColumnName+'])
REFERENCES ['+@PKTableName+'] (['+@PKcolumnName+'])'
PRINT(@sql)
SET @sql = 'ALTER TABLE '+@table+' CHECK CONSTRAINT '+@FKName
PRINT(@sql)
FETCH NEXT FROM table_cur2 INTO @table,@FKColumnName,@FKName
END
CLOSE table_cur2
DEALLOCATE table_cur2
DROP TABLE FKAgainstTableList
这是覆盖原始密钥的快捷方式:
CREATE UNIQUE CLUSTERED INDEX [pk_name] ON [table_name]([id])
WITH DROP_EXISTING
正如其他答案中所述,如果存在,您仍然需要删除/重新添加外部约束。
为 Jerloldrartolf 的答案添加双引号
IF EXISTS (SELECT * FROM sys.tables WHERE object_id = OBJECT_ID(N'[dbo].[FKAgainstTableList]'))
BEGIN
DROP TABLE FKAgainstTableList
END
--CREATE TABLE FKAgainstTableList (ForeignKey VARCHAR(30),[Table] VARCHAR(30))
DECLARE @PKTableName VARCHAR(100),
@PKName varchar(100),
@FKName varchar(100),
@sql varchar(max),
@PKcolumnName varchar(30),
@table VARCHAR(100),
@FKColumnName VARCHAR(100),
@parentColumnNumber int
SET @PKTableName = 'mytable'
set @PKName = (SELECT name FROM sys.indexes WHERE OBJECT_NAME(object_id) = @PKTableName AND is_primary_key = 1)
set @PKcolumnName = (SELECT name FROM sys.columns WHERE OBJECT_NAME(object_id) = @PKTableName AND is_identity =1)
PRINT @PKcolumnName
SELECT OBJECT_NAME(sys.foreign_key_columns.parent_object_id) [Table],sys.columns.name [FKColumnName],sys.foreign_keys.name [FKName]
INTO FKAgainstTableList
FROM sys.foreign_keys INNER JOIN sys.foreign_key_columns
ON sys.foreign_keys.object_id = sys.foreign_key_columns.constraint_object_id
INNER JOIN sys.columns ON sys.columns.object_id = sys.foreign_keys.parent_object_id AND sys.columns.column_id = sys.foreign_key_columns.parent_column_id
WHERE OBJECT_NAME(sys.foreign_keys.referenced_object_id) = @PKTableName
DECLARE table_cur1 CURSOR FOR
SELECT * FROM FKAgainstTableList
PRINT @sql
-------------------------------Disable constraint on FK Tables
OPEN table_cur1
FETCH NEXT FROM table_cur1 INTO @table,@FKColumnName,@FKName
WHILE @@FETCH_STATUS = 0
BEGIN
SET @sql ='ALTER TABLE '+@table+' DROP CONSTRAINT "'+ @FKName+'"'
PRINT @sql
FETCH NEXT FROM table_cur1 INTO @table,@FKColumnName,@FKName
END
CLOSE table_cur1
DEALLOCATE table_cur1
--------------------------------DROP AND recreate CLUSTERED pk
IF EXISTS (SELECT 1 FROM sys.indexes WHERE object_id = OBJECT_ID(@PKTableName) AND name = @PKName)
BEGIN
SET @sql = 'ALTER TABLE '+@PKTableName+' DROP CONSTRAINT "'+ @PKName +'"'
PRINT @sql
END
SET @sql = 'ALTER TABLE '+@PKTableName +' ADD CONSTRAINT '+@PKName+' PRIMARY KEY CLUSTERED ('+@PKcolumnName+' ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY]'
PRINT(@sql)
--------------------------------Enable FK constraints on FK tables.
DECLARE table_cur2 CURSOR FOR
SELECT * FROM FKAgainstTableList
OPEN table_cur2
FETCH NEXT FROM table_cur2 INTO @table,@FKColumnName,@FKName
WHILE @@FETCH_STATUS = 0
BEGIN
SET @sql = 'ALTER TABLE '+@table+' WITH NOCHECK ADD CONSTRAINT "'+ @FKName+'" FOREIGN KEY(['+@FKColumnName+'])
REFERENCES ['+@PKTableName+'] (['+@PKcolumnName+'])'
PRINT(@sql)
SET @sql = 'ALTER TABLE '+@table+' CHECK CONSTRAINT "'+@FKName+'"'
PRINT(@sql)
FETCH NEXT FROM table_cur2 INTO @table,@FKColumnName,@FKName
END
CLOSE table_cur2
DEALLOCATE table_cur2
DROP TABLE FKAgainstTableList
我发现我需要分 3 部分运行生成的脚本
从这部分产生的一代是中间部分。
SET @sql = 'ALTER TABLE '+@PKTableName +' ADD CONSTRAINT '+@PKName+' PRIMARY KEY CLUSTERED ('+@PKcolumnName+' ASC)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY]'
PRINT(@sql)
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