Run Migrations

Add compositions table

Now that we’ve got our first migration written, let’s try to run it and see what it does. Ecto provides a mix task to do this, so let’s jump down to the command line and run mix ecto.migrate.

You should see something like this:

This tells us that the migration was successful and Ecto added our new table.

Take a peek at the database to see the changes

Let’s take a look at our database and see what it did.

We’re going to open our database console to examine the tables directly. The following examples will show the steps for working with PostgreSQL.

We can open up a PostgreSQL console with the following command:

music_db=#

From here, we can use the \dt command to see a list of tables:

• music_db=# \dt

Here, in the middle, we can see our new compositions table. Let’s look at the details of that table using the \d command:

• music_db=# \d compositions

Primary key

We’ve truncated some of the output to fit in the ...