解析SQL表结构信息查询含主外键、自增长_MySQL-mysql教程

bitsCN.com 最近项目需要做什么数据字典，需要表结构信息。在网上看了许多关于表结构信息的查询，感觉都不怎么样。相对好一点就是《基于SQL2005 SQL2008 表结构信息查询升级版的详解(含外键信息)》 ，但是这里有一点小问题，缺少一个过滤以致运行有一点小bug。在AdventureWorks2012数据库中的Address表查询结果如图：

在查询过滤中我们添加以下信息就ok了：
AND g.class_desc = 'OBJECT_OR_COLUMN'
修改后的SQL如下：

SELECT 表名 = CASE WHEN a.colorder = 1 THEN d.name
ELSE ''
END ,
表说明 = CASE WHEN a.colorder = 1 THEN ISNULL(f.value, '')
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 dbo.sysindexes si
INNER JOIN dbo.sysindexkeys sik ON si.id = sik.id
AND si.indid = sik.indid
INNER JOIN dbo.syscolumns sc ON sc.id = sik.id
AND sc.colid = sik.colid
INNER JOIN dbo.sysobjects so ON so.name = so.name
AND so.xtype = 'PK'
WHERE sc.id = a.id
AND sc.colid = a.colid ) THEN '√'
ELSE ''
END ,
外键 = CASE WHEN tony.fkey IS NOT NULL
AND tony.fkey = a.colid THEN '√'
ELSE ''
END ,
外键表 = CASE WHEN tony.fkey IS NOT NULL
AND tony.fkey = a.colid THEN OBJECT_NAME(tony.fkeyid)
ELSE ''
END ,
外键字段 = CASE WHEN tony.fkey IS NOT NULL
AND tony.fkey = a.colid
THEN ( SELECT name
FROM syscolumns
WHERE colid = tony.fkey
AND id = tony.fkeyid
)
ELSE ''
END ,
类型 = b.name ,
长度 = a.length ,
精度 = 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], '') ,
创建时间 = d.crdate ,
更改时间 = CASE WHEN a.colorder = 1 THEN d.refdate
ELSE NULL
END
FROM dbo.syscolumns a
LEFT JOIN dbo.systypes b ON a.xtype = b.xusertype
INNER JOIN dbo.sysobjects d ON a.id = d.id
AND d.xtype = 'U'
AND d.status >= 0
LEFT JOIN dbo.syscomments e ON a.cdefault = e.id
LEFT JOIN sys.extended_properties g ON a.id = g.major_id
AND a.colid = g.minor_id
AND g.class_desc = 'OBJECT_OR_COLUMN'
LEFT JOIN sys.extended_properties f ON d.id = f.major_id
AND f.minor_id = 0
LEFT JOIN sysobjects htl ON htl.parent_obj = d.id
AND htl.xtype = 'F'
LEFT JOIN sysforeignkeys tony ON htl.id = tony.constid
WHERE d.name = 'Address' --这里输入包含表名称的条件
ORDER BY d.id ,
a.colorder

运行结果如图：

我不怎么喜欢它的“类型”信息，一般的varchar都会有长度信息，还有这个查询对于SQL 2012的新数据类型不支持，该SQL里面的嵌套查询比较多，于是我就自己重新写了一个SQL。
这里提醒大家尽量用INFORMATION_SCHEMA.XXX视图而不去用sys.XXX视图。
新的SQL如下：

SELECT
--OBJECT_ID(a.TABLE_SCHEMA + '.' + a.TABLE_NAME) AS [object_id] ,
CASE WHEN a.ORDINAL_POSITION = 1
THEN a.TABLE_SCHEMA + '.' + a.TABLE_NAME
ELSE ''
END AS TABLE_NAME ,
CASE WHEN ( a.ORDINAL_POSITION = 1
AND p1.value IS NOT NULL
) THEN p1.value
ELSE ''
END AS TABLE_Description ,
a.COLUMN_NAME ,
CASE WHEN ( ( CHARINDEX('char', a.DATA_TYPE) > 0
OR CHARINDEX('binary', a.DATA_TYPE) > 0
)
AND a.CHARACTER_MAXIMUM_LENGTH <> -1
)
THEN a.DATA_TYPE + '('
+ CAST(a.CHARACTER_MAXIMUM_LENGTH AS VARCHAR(4)) + ')'
WHEN ( ( CHARINDEX('CHAR', a.DATA_TYPE) > 0
OR CHARINDEX('binary', a.DATA_TYPE) > 0
)
AND a.CHARACTER_MAXIMUM_LENGTH = -1
) THEN a.DATA_TYPE + '(max)'
WHEN ( CHARINDEX('numeric', a.DATA_TYPE) > 0 )
THEN a.DATA_TYPE + '(' + CAST(a.NUMERIC_PRECISION AS VARCHAR(4))
+ ',' + CAST(a.NUMERIC_SCALE AS VARCHAR(4)) + ')'
ELSE a.DATA_TYPE
END AS COLUMN_TYPE ,
CASE WHEN c.IS_IDENTITY = 1 THEN 'YES'
ELSE 'NO'
END AS IS_IDENTITY ,
a.IS_NULLABLE ,
CASE WHEN a.COLUMN_DEFAULT IS NULL THEN ''
ELSE a.COLUMN_DEFAULT
END AS Default_Value ,
CASE WHEN p.value IS NULL THEN ''
ELSE p.value
END AS [COLUMN_Description] ,
CASE WHEN o.name IS NULL THEN ''
ELSE '√'
END AS Is_PrimaryKey ,
CASE WHEN f.parent_column_id IS NULL THEN ''
ELSE '√'
END AS Is_Foreignkeys ,
CASE WHEN referenced_object_id IS NULL THEN ''
ELSE OBJECT_NAME(referenced_object_id)
END AS Foreign_Table ,
CASE WHEN referenced_object_id IS NULL THEN ''
ELSE ( SELECT name
FROM sys.columns
WHERE object_id = f.referenced_object_id
AND column_id = f.referenced_column_id
)
END AS Foreign_key
FROM INFORMATION_SCHEMA.COLUMNS a
INNER JOIN sys.columns c ON OBJECT_ID(a.TABLE_SCHEMA + '.'
+ a.TABLE_NAME) = c.OBJECT_ID
AND a.COLUMN_NAME = c.NAME
LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE b ON a.TABLE_SCHEMA = b.TABLE_SCHEMA
AND a.TABLE_NAME = b.TABLE_NAME
AND a.COLUMN_NAME = b.COLUMN_NAME
LEFT JOIN sys.sysobjects o ON o.name = b.CONSTRAINT_NAME
AND o.xtype = 'PK'
LEFT JOIN sys.extended_properties p ON OBJECT_ID(a.TABLE_SCHEMA + '.'
+ a.TABLE_NAME) = p.major_id
AND a.Ordinal_position = p.minor_id
AND p.class_desc = 'OBJECT_OR_COLUMN'
LEFT JOIN sys.extended_properties p1 ON OBJECT_ID(a.TABLE_SCHEMA + '.'
+ a.TABLE_NAME) = p1.major_id
AND p1.minor_id = 0
LEFT JOIN SYS.foreign_key_columns f ON OBJECT_ID(a.TABLE_SCHEMA + '.'
+ a.TABLE_NAME) = f.parent_object_id
AND a.ORDINAL_POSITION = f.parent_column_id
WHERE a.TABLE_NAME = 'Address'
-- a.TABLE_NAME IN (SELECT name FROM sys.tables)
ORDER BY a.TABLE_SCHEMA,a.TABLE_NAME, a.ORDINAL_POSITION

运行效果如图：

有不对的地方还请大家拍砖！谢谢！bitsCN.com