SQL2005系统升级手记之四-自动生成数据字典与系统表Sys.extended_properites

最新推荐文章于 2020-12-24 15:46:57 发布

原创最新推荐文章于 2020-12-24 15:46:57 发布 · 848 阅读

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#sql #sql server #join #脚本 #数据库 #文档

本文档详细记录了如何使用SQL2005自动生成数据字典的过程，重点讲解了通过系统表`Sys.extended_properties`获取表、字段的元数据信息，包括表名、字段名、类型、长度、标识、主键、是否允许空值以及默认值等关键信息。此外，还展示了查询脚本，帮助理解如何利用`JOIN`操作从多个系统表中获取数据。

SQL2005系统升级手记之四-自动生成数据字典与系统表Sys.extended_properites

在SQL Server 2000 中，好多人都喜欢在表和列的扩展属性里面添加说明，然后用脚本生成数据库字典，升级到SQL Server 2005 后，会发现SQL Server 2000上的脚本不能使用了，其中绝大多数都是因为SQL Server 2005已经废弃了系统表 sysproperties。
注意， sysproperties 因为是无正式文档记载的系统表，已经在 Sql2005 中废弃了， Sql2005 中使用 Sys.extended_properites 保存用户自定义的表、字段的属性信息。

原先的脚本：

SELECT
2

( case when a.colorder = 1 then d.name else '' end )表名,
3

a.colorder 字段序号,
4

a.name 字段名,
5

( case when COLUMNPROPERTY ( a.id,a.name, ' IsIdentity ' ) = 1 then ' √ ' else '' end ) 标识,
6

( case when ( SELECT count ( * )
7

FROM sysobjects
8

WHERE (name in
9

( SELECT name
10

FROM sysindexes
11

WHERE (id = a.id) AND (indid in
12

( SELECT indid
13

FROM sysindexkeys
14

WHERE (id = a.id) AND (colid in
15

( SELECT olid
16

FROM yscolumns
17

WHERE (id = a.id) AND (name = a.name))))))) AND
18

(xtype = ' PK ' )) > 0 then ' √ ' else '' end ) 主键,
19

b.name 类型,
20

a.length 占用字节数,
21

COLUMNPROPERTY (a.id,a.name, ' PRECISION ' ) as 长度,
22

isnull ( COLUMNPROPERTY (a.id,a.name, ' Scale ' ), 0 ) as 小数位数,
23

( case when a.isnullable = 1 then ' √ ' else '' end ) 允许空,
24

isnull (e. text , '' ) 默认值,
25

isnull (g. [ value ] , '' ) AS 字段说明
26

FROM syscolumns a left join systypes b
28

on a.xtype = b.xusertype
29

inner join sysobjects d
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on a.id = d.id and d.xtype = ' U ' and .name <> ' dtproperties '
31

left join syscomments e
32

on a.cdefault = e.id
33

left join sysproperties g
34

on a.id = g.id AND a.colid = g.smallid
35

order by a.id,a.colorder

改为

1SELECT
2       (case when a.colorder=1 then d.name else '' end)表名,
3       a.colorder 字段序号,
4       a.name 字段名,
5       (case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end) 标识,
6       (case when (SELECT count(*)
7       FROM sysobjects
8       WHERE (name in
9                 (SELECT name
10                FROM sysindexes
11                WHERE (id = a.id) AND (indid in
12                          (SELECT indid
13                         FROM sysindexkeys
14                         WHERE (id = a.id) AND (colid in
15                                   (SELECT colid
16                                  FROM syscolumns
17                                  WHERE (id = a.id) AND (name = a.name))))))) AND
18              (xtype = 'PK'))>0 then '√' else '' end) 主键,
19       b.name 类型,
20       a.length 占用字节数,
21       COLUMNPROPERTY(a.id,a.name,'PRECISION') as 长度,
22       isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0) as 小数位数,
23       (case when a.isnullable=1 then '√'else '' end) 允许空,
24       isnull(e.text,'') 默认值,
25       isnull(g.[value],'') AS 字段说明
26
27FROM  syscolumns  a left join systypes b
28on  a.xtype=b.xusertype
29inner join sysobjects d
30on a.id=d.id  and  d.xtype='U' and  d.name<>'dtproperties'
31left join syscomments e
32on a.cdefault=e.id
33left join sys.extended_properties g
34on a.id=g.major_id AND a.colid = g.minor_id

35order by a.id,a.colorder
36