管理数据库Database

--创建一个数据库
createdb gtlions;
create database gtlions;
createdb -T template0 databasename;
create database gtlions template template0 tablespace gtlions_ts1;
alter database gtlions rename to gtlions1;
alter database gtlions set default_tablespace=gtlions_ts1;
alter database gtlions reset default_tablespace;
alter database gtlions owner to gtlions;
创建一个数据库默认会使用模板库template1克隆一个新库，这个模板包含了一些内置的对象；如果想获得一个干净的数据库，使用template0模板。创建数据库之后我们可以修改数据库的属主。
postgres=# create database gtlions;
CREATE DATABASE
postgres=# create user gtlions superuser;  
CREATE ROLE
postgres=# alter database gtlions owner to gtlions;  

ALTER DATABASE

postgres=# \l
                  List of databases
   Name    |  Owner  | Encoding |  Access privileges  
-----------+---------+----------+---------------------
 gtlions   | gtlions | UTF8     |
 postgres  | gpadmin | UTF8     |
 template0 | gpadmin | UTF8     | =c/gpadmin          
                                : gpadmin=CTc/gpadmin
 template1 | gpadmin | UTF8     | =c/gpadmin          
                                : gpadmin=CTc/gpadmin
(4 rows)

postgres=# \c gtlions
You are now connected to database "gtlions" as user "gpadmin".
postgres=# select * from pg_database;
  datname  | datdba | encoding | datistemplate | datallowconn | datconnlimit | datlastsysoid | datfrozenxid | dattablespace | datconfig |              datacl  

-----------+--------+----------+---------------+--------------+--------------+---------------+--------------+---------------+-----------+----------------------------------
 postgres  |     10 |        6 | t             | t            |           -1 |         10899 |          803 |          1663 |           |
 template1 |     10 |        6 | t             | t            |           -1 |         10899 |          803 |          1663 |           | {=c/gpadmin,gpadmin=CTc/gpadmin}
 template0 |     10 |        6 | t             | f            |           -1 |         10899 |          803 |          1663 |           | {=c/gpadmin,gpadmin=CTc/gpadmin}
 gtlions   |  98690 |        6 | f             | t            |           -1 |         10899 |          803 |          1663 |           |
(4 rows)
gtlions=# select datname,datdba,usename,encoding,pg_encoding_to_char(encoding) from pg_database a,pg_user b where a.datname='gtlions' and a.datdba=b.usesysid;
 datname | datdba | usename | encoding | pg_encoding_to_char
---------+--------+---------+----------+---------------------
 gtlions |  98690 | gtlions |        6 | UTF8
(1 row)

-EOF-