How to setup PostgreSQL on MacOS

This is a tutorial for setting up PostgreSQL on MacOS. You might be wondering why there's a need for another setup guide for Postgres in the first place, since there are a few across the web. I found many tutorials and guides on how to set it up, but found most of them to be unclear and outdated, based on old PostgreSQL versions. The checklist is not comprehensive, though, as it is used for several tutorials on my website, I keep it updated with the recent versions of PostgreSQL. If you spot any flaws in this guide, a comment below would be very helpful to keep it up to date for other developers.

If you want to run PostgreSQL on Windows instead, you will find guidance over here: How to setup PostgreSQL on Windows.

PostgreSQL Installation on MacOS

I recommend Homebrew for installing and managing applications on MacOS. It is installed using the following command in the MacOS terminal:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

The terminal runs through a series of installation operations, and will probably create folders in your local machine to accommodate Homebrews storage requirements. You can find more detailed instructions here. After it's installed, update the Homebrew dependencies and install PostgreSQL on the command line:

brew update
brew install postgresql

Next, check your PostgreSQL version:

postgres --version
postgres (PostgreSQL) 12.2

The command line results will show the version you have installed on your local machine. I recommed using the latest version of libraries and software whenever possible to avoid compatibility issues with client-side applications.

How to create a physical PostgreSQL Database

Now you can initialize the physical space on your hard-disk to allocate databases. To do this, create a default postgres database on the command line in case it didn't happen automatically:

initdb /usr/local/var/postgres

You will see the error message: "initdb: directory "/usr/local/var/postgres" exists but is not empty" if the database was already created when you installed PostgreSQL. It means the folder where you are attempting to create a physical place for the database already has one. Either way, next you can move on to the next step.

When you connect to this physical database later, you will see an actual database which is called "postgres" as well. The postgres database is meant to be the default database for any third-party tools that you are using in combination with PostgreSQL. These tools attempt to make the default connection to this default database, so you shouldn't delete it.

How to start/stop a PostgreSQL Database

Let's see next how you can interact with the actual database. Manually start and stop your Postgres database server with the following commands:

pg_ctl -D /usr/local/var/postgres start
pg_ctl -D /usr/local/var/postgres stop

The terminal will confirm these operations with "server started" and "server stopped" feedback. You could also implement a script to start the server each time you boot up the machine, but I like to have control over when to start and stop my database server to avoid complications.

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 mydatabase
dropdb mydatabase

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 mydatabase

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 mydatabase;
DROP DATABASE mydatabase;

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 mydatabase - Connect to another database.
• \d - List the relations of your currently connected database.
• \d mytablename - Shows information for a specific table.