如何断开与数据库的连接并返回到 PostgreSQL 中的默认数据库？
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How to Disconnect from a database and go back to the default database in PostgreSQL?
提问by 09Q71AO534
I'm using PostgreSql version :
我正在使用 PostgreSql 版本：
postgres=# select version();
version
-------------------------------------------------------------
PostgreSQL 9.2.4, compiled by Visual C++ build 1600, 64-bit
(1 row)
i had connected to a database from postgres=#to newdb=#....
Now i'm in newdb=#Database i want to disconnect it and go back to postgres=#database ....
我从连接到数据库postgres=#来newdb=#....现在我在newdb=#数据库中，我想拔掉，然后返回到postgres=#数据库....
How to do this ?
这该怎么做 ？
I have tried with disconnect newdb;
我试过 disconnect newdb;
but its giving erroe as::
但它给出的错误是：
postgres=# create database newdb;
CREATE DATABASE
postgres=# \c newdb;
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
You are now connected to database "newdb" as user "postgres".
newdb=# disconnect newdb;
ERROR: syntax error at or near "disconnect"
LINE 1: disconnect newdb;
^
newdb=#
it isnt working is there any other way to do this or am i wrong in anything!!
它不起作用有没有其他方法可以做到这一点，或者我有什么问题！！
回答by francs
It's easy, just look the example.
很简单，看例子就知道了。
--my databases
--我的数据库
postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+---------+-------+---------------------------
francs | postgres | UTF8 | C | C | =Tc/postgres +
| | | | | postgres=CTc/postgres +
| | | | | francs=C*T*c*/postgres +
| | | | | select_only=c/francs
postgres | postgres | UTF8 | C | C |
source_db | postgres | UTF8 | C | C | =Tc/postgres +
| | | | | postgres=CTc/postgres +
| | | | | source_db=C*T*c*/postgres
template0 | postgres | UTF8 | C | C | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | C | C | =c/postgres +
| | | | | postgres=CTc/postgres
(5 rows)
--switch to db francs as role francs
--切换到 db francs 作为角色 francs
postgres=# \c francs francs
You are now connected to database "francs" as user "francs".
--swith to db postgres as role postgres
--切换到 db postgres 作为角色 postgres
francs=> \c postgres postgres
You are now connected to database "postgres" as user "postgres".
postgres=#
--disconnect from db
--与数据库断开连接
postgres=# \q
回答by Hawkez
There is not a 'disconnect' in psql. Instead of disconnecting from your newdb database you connect with the default postgres database.
psql 中没有“断开连接”。与默认的 postgres 数据库连接，而不是与 newdb 数据库断开连接。
Create the new database and connect to it:
创建新数据库并连接到它：
postgres=# create database newdb;
CREATE DATABASE
postgres=# \c newdb
You are now connected to database "newdb" as user "postgres".
newdb=#
List the number of connections on newdb:
列出 newdb 上的连接数：
newdb=# select datname,numbackends from pg_stat_database where datname='newdb';
datname | numbackends
---------+-------------
newdb | 1
Now, instead of disconnecting, just connect with the default postgres database.
现在，无需断开连接，只需连接默认的 postgres 数据库即可。
newdb=# \c postgres
You are now connected to database "postgres" as user "postgres".
postgres=#
Now there are no connections on newdb:
现在newdb上没有连接：
postgres=# select datname,numbackends from pg_stat_database where datname='newdb';
datname | numbackends
---------+-------------
newdb | 0
