Playing with Postgres

After Postgres is installed, a database system is created, a postmaster daemon is running, and the regression tests have passed, you'll want to see Postgres do something. That's easy. Invoke the interactive interface to Postgres, psql:

% psql template1

(psql has to open a particular database, but at this point the only one that exists is the template1 database, which always exists. We will connect to it only long enough to create another one and switch to it.)

The response from psql is:

Welcome to the POSTGRESQL interactive sql monitor:
  Please read the file COPYRIGHT for copyright terms of POSTGRESQL

   type \? for help on slash commands
   type \q to quit
   type \g or terminate with semicolon to execute query
 You are currently connected to the database: template1

template1=>

Create the database foo:

template1=> create database foo;
CREATEDB

(Get in the habit of including those SQL semicolons. Psql won't execute anything until it sees the semicolon or a "\g" and the semicolon is required to delimit multiple statements.)

Now connect to the new database:

template1=> \c foo
connecting to new database: foo

("slash" commands aren't SQL, so no semicolon. Use \? to see all the slash commands.)

And create a table:

foo=> create table bar (i int4, c char(16));
CREATE

Then inspect the new table:

foo=> \d bar

Table    = bar
+----------------------------------+----------------------------------+-------+
|              Field               |              Type                | Length|
+----------------------------------+----------------------------------+-------+
| i                                | int4                             |     4 |
| c                                | (bp)char                         |    16 |
+----------------------------------+----------------------------------+-------+

And so on. You get the idea.