This chapter explains various methods of accessing the database. Assume that we have already created a database in our previous chapter. You can select the database using either of the following methods −

• Database SQL Prompt
• OS Command Prompt

Database SQL Prompt

Assume you have already launched your PostgreSQL client and you have landed at the following SQL prompt −

postgres=#

You can check the available database list using l, i.e., backslash el command as follows −

postgres-# l
                             List of databases
   Name    |  Owner   | Encoding | Collate | Ctype |   Access privileges
-----------+----------+----------+---------+-------+-----------------------
 postgres  | postgres | UTF8     | C       | C     |
 template0 | postgres | UTF8     | C       | C     | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
 template1 | postgres | UTF8     | C       | C     | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
 testdb    | postgres | UTF8     | C       | C     |
(4 rows)

postgres-#

Now, type the following command to connect/select a desired database; here, we will connect to the testdb database.

postgres=# c testdb;
psql (9.2.4)
Type "help" for help.
You are now connected to database "testdb" as user "postgres".
testdb=#

OS Command Prompt

You can select your database from the command prompt itself at the time when you login to your database. Following is a simple example −

psql -h localhost -p 5432 -U postgress testdb
Password for user postgress: ****
psql (9.2.4)
Type "help" for help.
You are now connected to database "testdb" as user "postgres".
testdb=#

You are now logged into PostgreSQL testdb and ready to execute your commands inside testdb. To exit from the database, you can use the command q.