实用技巧：利用SQL Server的扩展属性自动生成数据字典
可能是我太落伍了，今天才知道SQL2005的扩展属性还可以这么用。
数据字典的重要性就不用多说了，再小的开发团队，甚至只有一个人，这个东西也不可或缺，否则日后发生问题那才要命
以前的数据字典都要单独拿出时间来进行整理，但问题多多，最明显的就是和数据结构的变化不同步，而且耗时费力，效果底下
但稍微有点责任心的数据库维护人员，在编辑数据库对象时，都会习惯性的编写备注描述
以前SQL2K时，表备注、字段备注都是直接写在名称后面，SQL会将这些信息保存到系统表：sysproperties
但到了SQL2005，这些备注都转移到了扩展属性里，类似的，SQL会将这些信息保存到系统表：sys.extended_properties
填写表扩展属性的截图：
在SSMS里，在表或者字段上右键，选“属性”，都可以看到“扩展属性”页，其中：
属性名称建议填写固定值：MS_Description，据说这样可以兼容其他的数据字典工具，方便其提取
属性值可以填写表或者字段的详细备注信息
可以为一个表或者字段添加多个扩展属性。
扩展属性可以跟随数据库备份及还原操作进行传递与分发
那么，如果已经填写了扩展属性，该如何自动生成数据字典呢？
首先需要对SSMS输出的文本格式进行一下变动：
不要选中：在结果集中包括列标题，如图：
然后，新建查询窗口，并选择：以文本格式显示结果，如图：
重点来了，复制以下的T-SQL脚本，并执行：
Set nocount on DECLARE @TableName nvarchar(35) DECLARE Tbls CURSOR FOR Select distinct Table_name FROM INFORMATION_SCHEMA.COLUMNS --put any exclusions here --where table_name not like '%old' order by Table_name OPEN Tbls PRINT '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">' PRINT '<html xmlns="http://www.w3.org/1999/xhtml">' PRINT '<head>' PRINT '<title>数据库字典</title>' PRINT '<style type="text/css">' PRINT 'body{margin:0; font:11pt "arial", "微软雅黑"; cursor:default;}' PRINT '.tableBox{margin:10px auto; padding:0px; width:1000px; height:auto; background:#FBF5E3; border:1px solid #45360A}' PRINT '.tableBox h3 {font-size:12pt; height:30px; line-height:30px; background:#45360A; padding:0px 0px 0px 15px; color:#FFF; margin:0px; text-align:left }' PRINT '.tableBox table {width:1000px; padding:0px }' PRINT '.tableBox th {height:25px; border-top:1px solid #FFF; border-left:1px solid #FFF; background:#F7EBC8; border-right:1px solid #E0C889; border-bottom:1px solid #E0C889 }' PRINT '.tableBox td {height:25px; padding-left:10px; border-top:1px solid #FFF; border-left:1px solid #FFF; border-right:1px solid #E0C889; border-bottom:1px solid #E0C889 }' PRINT '</style>' PRINT '</head>' PRINT '<body>' FETCH NEXT FROM Tbls INTO @TableName WHILE @@FETCH_STATUS = 0 BEGIN PRINT '<div class="tableBox">' Select '<h3>' + @TableName + ' : '+cast(Value as varchar(1000)) + '</h3>' FROM sys.extended_properties A WHERE A.major_id = OBJECT_ID(@TableName) and name = 'MS_Description' and minor_id = 0 PRINT '<table cellspacing="0">' --Get the Description of the table --Characters 1-250 PRINT '<tr>' --Set up the Column Headers for the Table PRINT '<th>字段名称</th>' PRINT '<th>描述</th>' PRINT '<th>主键</th>' PRINT '<th>外键</th>' PRINT '<th>类型</th>' PRINT '<th>长度</th>' PRINT '<th>数值精度</th>' PRINT '<th>小数位数</th>' PRINT '<th>允许为空</th>' PRINT '<th>计算列</th>' PRINT '<th>标识列</th>' PRINT '<th>默认值</th>' --Get the Table Data SELECT '</tr><tr>', '<td>' + CAST(clmns.name AS VARCHAR(35)) + '</td>', '<td>' + ISNULL(CAST(exprop.value AS VARCHAR(500)),'') + '</td>', '<td>' + CAST(ISNULL(idxcol.index_column_id, 0)AS VARCHAR(20)) + '</td>', '<td>' + CAST(ISNULL( (SELECT TOP 1 1 FROM sys.foreign_key_columns AS fkclmn WHERE fkclmn.parent_column_id = clmns.column_id AND fkclmn.parent_object_id = clmns.object_id ), 0) AS VARCHAR(20)) + '</td>', '<td>' + CAST(udt.name AS CHAR(15)) + '</td>' , '<td>' + CAST(CAST(CASE WHEN typ.name IN (N'nchar', N'nvarchar') AND clmns.max_length <> -1 THEN clmns.max_length/2 ELSE clmns.max_length END AS INT) AS VARCHAR(20)) + '</td>', '<td>' + CAST(CAST(clmns.precision AS INT) AS VARCHAR(20)) + '</td>', '<td>' + CAST(CAST(clmns.scale AS INT) AS VARCHAR(20)) + '</td>', '<td>' + CAST(clmns.is_nullable AS VARCHAR(20)) + '</td>' , '<td>' + CAST(clmns.is_computed AS VARCHAR(20)) + '</td>' , '<td>' + CAST(clmns.is_identity AS VARCHAR(20)) + '</td>' , '<td>' + isnull(CAST(cnstr.definition AS VARCHAR(20)),'') + '</td>' FROM sys.tables AS tbl INNER JOIN sys.all_columns AS clmns ON clmns.object_id=tbl.object_id LEFT OUTER JOIN sys.indexes AS idx ON idx.object_id = clmns.object_id AND 1 =idx.is_primary_key LEFT OUTER JOIN sys.index_columns AS idxcol ON idxcol.index_id = idx.index_id AND idxcol.column_id = clmns.column_id AND idxcol.object_id = clmns.object_id AND 0 = idxcol.is_included_column LEFT OUTER JOIN sys.types AS udt ON udt.user_type_id = clmns.user_type_id LEFT OUTER JOIN sys.types AS typ ON typ.user_type_id = clmns.system_type_id AND typ.user_type_id = typ.system_type_id LEFT JOIN sys.default_constraints AS cnstr ON cnstr.object_id=clmns.default_object_id LEFT OUTER JOIN sys.extended_properties exprop ON exprop.major_id = clmns.object_id AND exprop.minor_id = clmns.column_id AND exprop.name = 'MS_Description' WHERE (tbl.name = @TableName and exprop.class = 1) --I don't wand to include comments on indexes ORDER BY clmns.column_id ASC PRINT '</tr></table>' PRINT '</div>' FETCH NEXT FROM Tbls INTO @TableName END PRINT '</body></HTML>' CLOSE Tbls DEALLOCATE Tbls
执行完成后，会在结果窗口中打印出一大段HTML代码
复制这段HTML代码，新建一个.htm的WEB文件，粘贴进去，用浏览器打开即可阅读最新版的数据字典！
最终效果截图：
