SQL SERVER 
            查看所有表名:
            select    name    from    sysobjects    where    type='U'
            查询表的所有字段名:
            Select name from syscolumns Where ID=OBJECT_ID('表名')
            select * from information_schema.tables
            select * from information_schema.views
            select * from information_schema.columns 
            ACCESS
            查看所有表名:
            select    name    from    MSysObjects    where    type=1    and    flags=0
            MSysObjects是系统对象,默认情况是隐藏的。通过工具、选项、视图、显示、系统对象可以使之显示出来。  
             
             
             
             
            
             
             
            --获取表字段名称,属性
            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 sysobjects where xtype='PK' and parent_obj=a.id 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.xusertype=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 
            left join 
                sysproperties f 
            on 
                d.id=f.id and f.smallid=0
            where 
                d.name='要查询的表'    --如果只查询指定表,加上此条件
            order by 
                a.id,a.colorder
            
             
             
             
             
             
             
            --获取库中所有表字段的定义(包括名字,属性等)
            --1. SqlServer数据库字典--表结构.sql
             
            /**
            表a为syscolumns
            表b为systypes
            表d为sysobjects
            表e为syscomments
            表g为sysproperties
            */ 
            
            
            
            SELECT TOP 100 PERCENT --a.id, 
            
            CASE WHEN a.colorder = 1 THEN d.name ELSE '' END AS 表名, 
            
            CASE WHEN a.colorder = 1 THEN isnull(f.value, '') ELSE '' END AS 表说明, 
            
            a.colorder AS 字段序号, a.name AS 字段名, CASE WHEN COLUMNPROPERTY(a.id, 
            
            a.name, 'IsIdentity') = 1 THEN '√' ELSE '' END AS 标识, 
            
            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 AS 主键, 
            
            b.name AS 类型, a.length AS 长度, COLUMNPROPERTY(a.id, a.name, 'PRECISION') 
            
            AS 精度, ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) AS 小数位数, 
            
            CASE WHEN a.isnullable = 1 THEN '√' ELSE '' END AS 允许空, ISNULL(e.text, '') 
            
            AS 默认值, ISNULL(g.[value], '') AS 字段说明, d.crdate AS 创建时间, 
            
            CASE WHEN a.colorder = 1 THEN d.refdate ELSE NULL END AS 更改时间 
            
            FROM dbo.syscolumns a LEFT OUTER 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 OUTER JOIN 
            
            dbo.syscomments e ON a.cdefault = e.id LEFT OUTER JOIN 
            
            dbo.sysproperties g ON a.id = g.id AND a.colid = g.smallid LEFT OUTER JOIN 
            
            dbo.sysproperties f ON d.id = f.id AND f.smallid = 0 
            
            ORDER BY d.name, a.colorder