得到PostgreSQL 数据库表字段的部分信息（Name,Type,Len,PK,AutoIncrease,AllowNullable）

为了找到这些信息我可以费老劲，发现 PostgreSQL 的一个可能的 Bug，还查看 PostgreSQL 的源码才猜到怎样能得到有自动增长属性的字段。不过总体上感觉比 MS SQL SERVER 的数据结构合理很多。大家可以去找找怎样得到主键属性的 MS SQL 语句。废话不多说，我把语句格式化了一下希望有助于阅读。帖出来算是对自由软件的微末贡献巴。语句虽然没有得到全部的信息，但比较难得到的都已列出来，其它的顺着这个思路应该问题不大。

select tbl.relname as TableName,
col.attname as ColumnName,
pg_type.typname as ColumnType,
(case when col.attlen<0 then col.atttypmod else col.attlen end) as ColumnLen,
(select count(*) from pg_constraint ct where ct.contype=p::char and col.attnum = any (conkey) and ct.conrelid=tbl.oid) as IsPk,
(case when seq.oid is null then 0 else 1 end) as IsAutoIncrease,
(case when col.attnotnull=false then 1 else 0 end) as AllowNullable
from pg_attribute col
inner join pg_class tbl on col.attrelid=tbl.oid and tbl.relkind=r::char
left join pg_depend dp on tbl.oid=dp.refobjid and col.attnum=dp.refobjsubid and deptype=i::char
left join pg_class seq on dp.objid=seq.oid and seq.relkind=S::char
inner join pg_namespace space on tbl.relnamespace=space.oid and space.nspname<>pg_catalog::name and space.nspname<>information_schema::name and space.nspname<>pg_toast::name
left join pg_type on col.atttypid=pg_type.oid 
where col.attnum>0 
order by tbl.relname, col.attnum

Links
PostgreSQL Official Site
PostgreSQL 中文站

 

在SQL SERVER2000中：

SELECT
(case when a.colorder=1 then d.name else '' end) N'表名',
a.colorder N'字段序号',
a.name N'字段名',
(case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end) N'标识',
(case when (SELECT count(*)
FROM sysobjects
WHERE (name in
(SELECT name
FROM sysindexes
WHERE (id = a.id) AND (indid in
(SELECT indid
FROM sysindexkeys
WHERE (id = a.id) AND (colid in
(SELECT colid
FROM syscolumns
WHERE (id = a.id) AND (name = a.name))))))) AND
(xtype = 'PK'))>0 then '√' else '' end) N'主键',
b.name N'类型',
a.length N'占用字节数',
COLUMNPROPERTY(a.id,a.name,'PRECISION') as N'长度',
isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0) as N'小数位数',
(case when a.isnullable=1 then '√'else '' end) N'允许空',
isnull(e.text,'') N'默认值',
isnull(g.[value],'') AS N'字段说明'
--into ##tx

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 object_name(a.id),a.colorder

 

在SQL Server2005中要用extended_properties 代替sysproperties。