How to switch databases in psql?

In MySQL, I开发者_如何学Python used use database_name;

What's the psql equivalent?

In PostgreSQL, you can use the \connect meta-command of the client tool psql:

\connect DBNAME

or in short:

\c DBNAME

You can connect to a database with \c <database> or \connect <database>.

At the PSQL prompt, you can do:

\connect (or \c) dbname

You can select the database when connecting with psql. This is handy when using it from a script:

sudo -u postgres psql -c "CREATE SCHEMA test AUTHORIZATION test;" test

use \c databaseName or \connect databaseName

(Working on psql 13.3)

\l for databases \c DatabaseName to switch to db \df for procedures stored in particular database

Though not explicitly stated in the question, the purpose is to connect to a specific schema/database.

Another option is to directly connect to the schema. Example:

sudo -u postgres psql -d my_database_name

Source from man psql:

-d dbname
--dbname=dbname
   Specifies the name of the database to connect to. This is equivalent to specifying dbname as the first non-option argument on the command line.

   If this parameter contains an = sign or starts with a valid URI prefix (postgresql:// or postgres://), it is treated as a conninfo string. See Section 31.1.1, “Connection Strings”, in the
   documentation for more information.

Using psql's meta-command \c or \connect [ dbname [ username ] [ host ] [ port ] ] | conninfo (see documentation).

Example: \c MyDatabase

Note that the \c and \connect meta-commands are case-sensitive.

Use below statement to switch to different databases residing inside your postgreSQL RDMS

\c databaseName

You can also connect to a database with a different ROLE as follows.

\connect DBNAME ROLENAME;

or

\c DBNAME ROLENAME;

If you want to switch to a specific database on startup, try

/Applications/Postgres.app/Contents/Versions/9.5/bin/psql vigneshdb;

By default, Postgres runs on the port 5432. If it runs on another, make sure to pass the port in the command line.

/Applications/Postgres.app/Contents/Versions/9.5/bin/psql -p2345 vigneshdb;

By a simple alias, we can make it handy.

Create an alias in your .bashrc or .bash_profile

function psql()
{
    db=vigneshdb
    if [ "$1" != ""]; then
            db=$1
    fi
    /Applications/Postgres.app/Contents/Versions/9.5/bin/psql -p5432 $1
}

Run psql in command line, it will switch to default database; psql anotherdb, it will switch to the db with the name in argument, on startup.

Listing and Switching Databases in PostgreSQL When you need to change between databases, you’ll use the \connect command, or \c followed by the database name as shown below:

postgres=# \connect database_name
postgres=# \c database_name

Check the database you are currently connected to.

SELECT current_database();

PostgreSQL List Databases

postgres=# \l
 postgres=# \list

You can connect using

\c dbname

If you would like to see all possible commands for POSTGRESQL or SQL follow this steps :

1. rails dbconsole (You will be redirected to your current ENV database)

2. ? (For POSTGRESQL commands)

or

2. \h (For SQL commands)

3. Press Q to Exit

  Connect to database:

  Method 1 : enter to db : sudo -u postgres psql

  Connect to db : \c dbname

  Method 2 : directly connect to db : sudo -u postgres psql -d my_database_name

You can just enter use [dbName] to switch between databases without reentering your password.