--pg_catalog
SELECT * from pg_class c,pg_attribute a,pg_type t where c.relname='BookKindList' and a.attnum>0 and a.attrelid=c.oid and a.atttypid=t.oid

SELECT a.attname from pg_class c,pg_attribute a,pg_type t where c.relname='BookKindList' and a.attnum>0 and a.attrelid=c.oid and a.atttypid=t.oid



--查询BookKindList表的字段信息 Geovin Du 涂聚文 20150402
SELECT a.attnum,a.attname AS field,t.typname AS type,a.attlen AS length,a.atttypmod AS lengthvar,a.attnotnull AS notnull from pg_class c,pg_attribute a,pg_type t where c.relname='BookKindList' and a.attnum>0 and a.attrelid=c.oid and a.atttypid=t.oid


SELECT * FROM information_schema.columns; 
--查表的列表
SELECT * FROM information_schema.columns where table_catalog='geovindu' and table_schema='public' and table_name='bookkindlist';
--
select * from pg_database where datname='bookkindlist';

select datname,dattablespace from pg_database where datname='bookkindlist';

--查看数据库
select * from pg_database;

--查看表空间
select * from pg_tablespace;
 
--查看语言
select * from pg_language;
 
--查看角色用户
select * from pg_user;
select * from pg_shadow;
select * from pg_roles;
 
--查看会话进程
select * from pg_stat_activity;
 
--查看表
SELECT * FROM pg_tables where schemaname = 'public';
 
--查看表字段
select * from information_schema.columns where table_schema = 'public' and table_name = 'bookkindlist';
 
--查看视图
select * from pg_views where schemaname = 'public';
select * from information_schema.views where table_schema = 'public';
 
--查看触发器
select * from information_schema.triggers;
 
--查看序列
select * from information_schema.sequences where sequence_schema = 'public';
 
 --查看约束
select * from pg_constraint where contype = 'p'  

--u unique,p primary,f foreign,c check,t trigger,x exclusion 
select a.relname as table_name,b.conname as constraint_name,b.contype as constraint_type from pg_class a,pg_constraint b where a.oid = b.conrelid and a.relname = 'bookkindlist';
 
--查看索引
select * from pg_index ;
 
--查看表上存在哪些索引以及大小
select relname,n.amname as index_type from pg_class m,pg_am n where m.relam = n.oid and m.oid in (
select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'bookkindlist');
 
SELECT c.relname,c2.relname, c2.relpages*8 as size_kb
FROM pg_class c, pg_class c2, pg_index i
WHERE c.relname = 'bookkindlist' AND
c.oid = i.indrelid AND
c2.oid = i.indexrelid
ORDER BY c2.relname; 
 
--查看索引定义
select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'bookkindlist';
select pg_get_indexdef(b.indexrelid);
 
--查看过程函数定义
select oid,* from pg_proc where proname = 'insert_platform_action_exist'; --oid = 24610
select * from pg_get_functiondef(24610);
 
--查看表大小(不含索引等信息)
select pg_relation_size('bookkindlist');                         --368640 byte
select pg_size_pretty(pg_relation_size('bookkindlist'))   --360 kB
 
--查看DB大小
select pg_size_pretty(pg_database_size('geovindu'));   --12M
 
--查看服务器DB运行状态
[postgres@192.168.20.165 ~]$ pg_ctl status -D $PGDATA
pg_ctl: server is running (PID: 2373)
/home/postgres/bin/postgres "-D" "/database/pgdata" 
 
--查看每个DB的使用情况(读,写,缓存,更新,事务等)
select * from pg_stat_database
 
--查看索引的使用情况
select * from pg_stat_user_indexes;
 
--查看表所对应的数据文件路径与大小
SELECT pg_relation_filepath(oid), relpages FROM pg_class WHERE relname = 'bookkindlist';
 
--查看索引与相关字段及大小
 SELECT n.nspname AS schema_name,
        r.rolname as table_owner,
       bc.relname AS table_name,
       ic.relname AS index_name,
       a.attname  AS column_name,
       bc.relpages*8 as index_size_kb     
  FROM pg_namespace n,
       pg_class bc,             -- base class
       pg_class ic,             -- index class
       pg_index i,
       pg_attribute a,           -- att in base
       pg_roles r
  WHERE bc.relnamespace = n.oid
     and i.indrelid = bc.oid
     and i.indexrelid = ic.oid
     and bc.relowner = r.oid
     and i.indkey[0] = a.attnum
     and i.indnatts = 1
     and a.attrelid = bc.oid
     and n.nspname = 'public'
     and bc.relname = 'bookkindlist'
  ORDER BY schema_name, table_name, index_name, attname;
 
--查看PG锁
select * from pg_locks;
 
备注:relpages*8 是实际所占磁盘大小
 
--查看表空间大小
select pg_tablespace_size('pg_default');
 
--查看序列与表的对应关系
  WITH fq_objects AS (SELECT c.oid,c.relname AS fqname ,
                           c.relkind, c.relname AS relation
                    FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace ),
 
     sequences AS (SELECT oid,fqname FROM fq_objects WHERE relkind = 'S'), 
     tables    AS (SELECT oid, fqname FROM fq_objects WHERE relkind = 'r' ) 
         SELECT
       s.fqname AS sequence,
       '->' as depends,
       t.fqname AS table
      FROM
       pg_depend d JOIN sequences s ON s.oid = d.objid 
                 JOIN tables t ON t.oid = d.refobjid 
          WHERE
       d.deptype = 'a' and t.fqname = 'bookkindlist';

--
select * from information_schema.columns where table_catalog= 'geovindu' AND table_name = 'bookkindlist';

select * from pg_description;



  ---一个查询表结构的SQL
  SELECT
    col.table_schema ,
    col.table_name ,
    col.ordinal_position,
    col.column_name ,
    col.data_type ,
    col.character_maximum_length,
    col.numeric_precision,
    col.numeric_scale,
    col.is_nullable,
    col.column_default ,
    des.description
FROM
    information_schema.columns col LEFT JOIN pg_description des
        ON col.table_name::regclass = des.objoid
    AND col.ordinal_position = des.objsubid
WHERE
    table_schema = 'public'
    AND table_name = 'bookkindlist'
ORDER BY
    ordinal_position;


select * from pg_namespace

select * from pg_class where relname='bookkindlist'
---
SELECT
n.nspname ,
relname
FROM
pg_class c ,
pg_namespace n
WHERE
c.relnamespace = n.oid
AND nspname='public'
AND relkind = 'r'
AND relhassubclass
ORDER BY
nspname ,
relname;
--
select * from information_schema.columns where table_name = 'bookkindlist';
--表结构
select table_schema,table_name,column_name,data_type,column_default,character_maximum_length,is_nullable from information_schema.columns where table_name = 'bookkindlist';
select table_schema,table_name,column_name as FieldName,data_type as   FieldType,column_default,character_maximum_length as   FieldLength,is_nullable from information_schema.columns where table_name = 'bookkindlist';
--表主键名称
select pg_constraint.conname as pk_name from pg_constraint  inner join pg_class  on pg_constraint.conrelid = pg_class.oid where pg_class.relname = 'bookkindlist' and pg_constraint.contype='p';

--表主键字段
select pg_constraint.conname as pk_name,pg_attribute.attname as column_name,pg_type.typname as data_type,pg_class.relname as table_name, info.character_maximum_length,info.is_nullable  from 
pg_constraint  inner join pg_class 
on pg_constraint.conrelid = pg_class.oid 
inner join pg_attribute on pg_attribute.attrelid = pg_class.oid 
and  pg_attribute.attnum = pg_constraint.conkey[1]
inner join pg_type on pg_type.oid = pg_attribute.atttypid
inner join information_schema.columns as info on info.column_name=pg_attribute.attname 

where pg_class.relname = 'bookkindlist' 
and pg_constraint.contype='p';


--表主键名称
select conname,conrelid,connamespace from pg_constraint where contype='p';

select * from pg_constraint where contype='p';
---表和表主键名称
select oid,relname from pg_class;

select * from pg_class where relnamespace=2200;

select * from pg_class;
--表
select * from pg_type where typnamespace=2200;
select typnamespace,typname,oid from pg_type where typnamespace=2200;


select * from pg_type where typname='bookkindlist';
-- 主键字段名attname

select * from pg_attribute;
select * from pg_attribute where attstorage='p';
select attrelid,attname,attnum from pg_attribute where attstorage='p';