2.创建数据库

HOW TO CREATE THE ACTUAL POSTGRESQL DATABASE

Next, let’s go through the steps of setting up a database that can be
used for one of your applications. Make sure the Postgre server is
started first, then type these commands in the command line to create
and remove a database:

createdb mydatabasename

dropdb mydatabasename

You can also connect to databases to execute SQL statements. Either use
the psql command, or specify a database such as the default postgres
database to connect:

psql mydatabasename

The command leads you to the psql shell, which you can exit by typing
CTRL + d. In the psql shell, you can create and drop databases as well:

CREATE DATABASE mydatabasename;

DROP DATABASE mydatabasename;

To list all your databases, you can type list. Your will see any new
databases listed, as well as two default databases that come with
postgreSQL called template0 and template1. The templates should remain
in your database list even if you aren’t using them, as they may be
useful later.

• list - List all of your actual databases.

• c mydatabasename - Connect to another database.

• d - List the relations of your currently connected database.

• d mytablename - Shows information for a specific table.

列出所有数据库：

psql -l

列出所有表格：

psql -dt+

或进入psql后使用dt+