剖析SQLSERVER2005的页面结构--表修改的内部处理篇
------------------------------------------------------------------ -- Author : HappyFlyStone -- Date : 2009-12-01 22 ： 00 ： 00 -- Version: Microsoft SQL Server 2005 - 9.00.2047.00 (Intel X86) -- Apr 14 2006 01:12:25 -- Copyright (c) 1988
------------------------------------------------------------------
-- Author : HappyFlyStone
-- Date : 2009-12-01 22：00：00
-- Version: Microsoft SQL Server 2005 - 9.00.2047.00 (Intel X86)
-- Apr 14 2006 01:12:25
-- Copyright (c) 1988-2005 Microsoft Corporation
-- Enterprise Edition on Windows NT 5.2 (Build 3790: SP2)
--
-------------------------------------------------------------------
create table altertb(id int identity(1,1),col char(100),int_col int)
go
insert into altertb
select REPLICATE('a',5),1 union all
select REPLICATE('b',5),2
go
alter table altertb
alter column col char(200) --
go
alter table altertb
alter column int_col tinyint –- 两个alter column 可同时执行
go
insert into altertb select 'cccc',3 –-观察新增加记录页面情况
go
dbcc ind(testcsdn,altertb,-1)--237
dbcc traceon(3604)
dbcc page(testcsdn,1,237,1)
drop table altertb
/*
DATA:
Slot 0, Offset 0x60, Length 115, DumpStyle BYTE
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP
Memory Dump @0x4343C060
00000000: 10007000 01000000 61616161 61202020 †..p.....aaaaa
00000010: 20202020 20202020 20202020 20202020 †
00000020: 20202020 20202020 20202020 20202020 †
00000030: 20202020 20202020 20202020 20202020 †
00000040: 20202020 20202020 20202020 20202020 †
00000050: 20202020 20202020 20202020 20202020 †
00000060: 20202020 20202020 20202020 01000000 † ....
00000070: 0300f8†††††††††††††††††††††††††††††††...
alter table altertb alter column col char(200) --
go
alter table altertb alter column int_col tinyint --
go
Slot 0, Offset 0x146, Length 315, DumpStyle BYTE
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP
Memory Dump @0x438DC146
00000000: 10003801 01000000 61616161 61202020 †..8.....aaaaa
00000010: 20202020 20202020 20202020 20202020 †
00000020: 20202020 20202020 20202020 20202020 †
00000030: 20202020 20202020 20202020 20202020 †
00000040: 20202020 20202020 20202020 20202020 †
00000050: 20202020 20202020 20202020 20202020 †
00000060: 20202020 20202020 20202020 01000000 † ....
00000070: 61616161 61202020 20202020 20202020 †aaaaa
00000080: 20202020 20202020 20202020 20202020 †
00000090: 20202020 20202020 20202020 20202020 †
......
00000120: 20202020 20202020 20202020 20202020 †
00000130: 20202020 20202020 0400f0††††††††††††† ...
insert into altertb select 'cccc',3
go
Slot 2, Offset 0x3bc, Length 315, DumpStyle BYTE
Record Type = PRIMARY_RECORD Record Attributes = NULL_BITMAP
Memory Dump @0x4343C3BC
00000000: 10003801 03000000 00000000 00ac0100 †..8.............
00000010: 0001001a 000300f8 16171900 0001e08d †................
00000020: 05000000 0000ac01 00000100 1b000300 †................
00000030: f8161819 00000104 43040000 000000ac †........C.......
00000040: 01000001 001c0003 00f81619 19000001 †................
00000050: 20300500 00000000 ac010000 01001d00 † 0..............
00000060: 0300f816 1a190000 0144a705 03000000 †.........D......
00000070: 63636363 20202020 20202020 20202020 †cccc
00000080: 20202020 20202020 20202020 20202020 †
......
00000120: 20202020 20202020 20202020 20202020 †
00000130: 20202020 20202020 0400f2††††††††††††† ...
*/