【IT168技术文档】

 　　由于写一个代码自动生成工具，需要找一些读系统数据字典的信息，以前有个写一个很不错的,

SELECT  表名=case when a.colorder=1 then d.name else '' end,
字段序号=a.colorder, 字段名=a.name, 标识=case
when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end,
主键=case when exists(SELECT 1 FROM sysobjects where xtype='PK'
and name in (  SELECT name FROM sysindexes
WHERE indid in(   SELECT indid FROM sysindexkeys WHERE id = a.id
AND colid=a.colid  ))) then '√' else '' end,
类型=b.name, 占用字节数=a.length, 长度=COLUMNPROPERTY(a.id,a.name,'PRECISION'),
小数位数=isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0),
允许空=case when a.isnullable=1 then '√'else '' end,
默认值=isnull(e.text,''), 字段说明=isnull(g.[value],'')
FROM syscolumns a left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id
and d.xtype='U' and  d.name<>'dtproperties'
left join syscomments e on a.cdefault=e.id
left join sysproperties g on a.id=g.id and a.colid=g.smallid
order by a.id,a.colorder

 　　我也按字的方法来读，但是今天发现，主键，信息不是很正确。一看代码，读主键，那要跟索引结合起来的。

 　　于是上网找相关资料，找了半天，也没有找到。于是就自己看SQL Server的帮助，最后发现，syscolumns的status为128就是主键。

SELECT ColumnName = a.name, Type = b.name,Length3 =COLUMNPROPERTY(a.id,a.name,'PRECISION'),
IsKey = CASE a.status WHEN 128
THEN '1' ELSE '0' END,
Length1 = a.length, Length2 = isnull(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0),
IsIdentity = CASE WHEN COLUMNPROPERTY(a.id, a.name, 'IsIdentity')  = 1 THEN '1' ELSE '0' END
FROM syscolumns a LEFT JOIN
systypes b ON a.xtype = b.xusertype INNER JOIN  sysobjects d ON a.id = d .id 
AND d .xtype = 'U' AND d .name <> 'dtproperties' LEFT
JOIN  syscomments e ON a.cdefault = e.id LEFT JOIN  sysproperties g ON a.id = g.id 
AND a.colid = g.smallid
WHERE d .name = 'Users' ORDER BY a.id, a.colorder