SQL Server 数据库结构查询

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SELECT (casewhen a.colorder=1then d.nameelsenullend)表名,a.colorder字段序号,a.name字段名,
(casewhen COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1then'√'else''end)标识,
(casewhen(SELECT count(*) FROM sysobjects WHERE(namein
(SELECT name FROM sysindexes WHERE (id= a.id) AND (indidin
(SELECT indid FROM sysindexkeys WHERE (id= a.id) AND (colidin
(SELECT colid FROM syscolumns WHERE (id= a.id) AND (name= a.name)))))))
AND(xtype='PK'))>0then'√'else''end)主键,b.name类型,a.length占用字节数,
COLUMNPROPERTY(a.id,a.name,'PRECISION')as长度,
isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0)as小数位数,(casewhen a.isnullable=1then'√'else''end)允许空,
isnull(e.text,'')默认值,isnull(g.[value],' ') AS[说明]
FROM syscolumns a
left join systypes b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.idand d.xtype='U'and d.name<>'dtproperties'
left join 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
left join sys.extended_properties f on d.id=f.classand f.minor_id=0
where b.nameisnotnull
orderby a.id,a.colorder

公司程序员更新好几代，但是数据库结构一直没变，而最初也没有规范的生成数据库字段解释文档，仅仅在程序中有注释。但苦逼测试怎么可能看到程序呢。一个数据库中所有表的结构可以用以上的语句查询，其中说明一栏一般情况下会有该字段的说明。如果是特定查询某个表的结构，可以将倒数第二行改为：

WHERE d.name='表名'

另外以下是一些可能会用到的数据库查询语句

1、查询服务器中所有数据库名称

SELECT Name FROM Master..SysDatabases ORDER BY Name

2、查询某个数据库都有些什么表

select*from表名.dbo.sysobjects
where xtype='U'
orderby name
其中各个xtype的解释如下：
AF = Aggregate function (CLR)                                                C = CHECK constraint
D = Default or DEFAULT constraint                                          F = FOREIGN KEY constraint
L = Log                                                                                     FN = Scalar function
FS = Assembly (CLR) scalar-function                                        FT = Assembly (CLR) table-valued function         
IF = In-lined table-function                                                       IT = Internal table
P = Stored procedure                                                              PC = Assembly (CLR) stored-procedure
PK = PRIMARY KEY constraint (type is K)                                 RF = Replication filter stored procedure
S = System table                                                                      SN = Synonym
SQ = Service queue                                                                  TA = Assembly (CLR) DML trigger
TF = Table function                                                                  TR = SQL DML Trigger
TT = Table type                                                                        U = User table
UQ = UNIQUE constraint (type is K)                                         V = View
X = Extended stored procedure

3、查询某个表的主键

SELECT  name FROM SysColumns 
WHERE id=Object_Id('表名') 
and colid=(select top 1 keyno from sysindexkeys where id=Object_Id('表名'))

4、查询某个表的数据的长度

select sum(Length) as Length_total from SysColumns
where id=Object_Id('表名')

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