Using Knex

Part 1: Migrations

Requirements

Let's create a database, fill it with useful tables, and then knock the whole thing down again.

First create a directory for your knex sand castle and cd into it

mkdir knex-sandcastle && cd $_
npm init -y
npm install --save pg knex`

Using your psql console,

psql
CREATE DATABASE sandcastledb;

HINT: don't forget the ";" at the end of the statement, and avoid capital letters.

knex init

Update your knexfile.js to use your sandcastledb.

knex migrate:make add_first_table

Put a table in the exports.up, and then drop the table in exports.down. What kind of table? How about some monsters (monsters like attacking castles). Monsters have names, unique IDs, and any other descriptive columns you feel like adding.

Now run knex migrate:latest and check to see if your "monsters" table has been added to your database using pgAdmin or your psql terminal.

It looks awesome? Let's get rid of it! knex migrate:rollback and check to make sure that table is gone.

All done!

Just kidding...

Try it again. Make another migration to add a second table to your database. How about some heroes to fight off those monsters? Run knex migrate:latest and knex migrate:rollback a couple of time to see how the two different migration intereact with each other and the databse.

Important: whenever you make a change to your database, you can migrate:latest, you can migrate:rollback, or you can migrate:make new_migration. Do not change a migration file that has already been made, or you will be sad 😢.

Bonus

• Create another migration that adds a new column to your hero table
• Create yet another migration that adds a weapons table to your database. The weapons should have names and should have a many to many relationship with your heroes.

Part 2: Seeding

Remember that sandcastle database we made in the previous exercise? Go ahead and run those migrations so that our tables exist, and let's seed them with data.

• Create a seed file for your monsters and add at least three monsters to your database.
• Create a new seed file for your heros and add those guys to the databse.
• Confirm your seeded data has made it into the database by checking pgAdmin or psql.
• Create a new table called "battles" that includes a unique id, a location, a hero id (foreign key), and a monster id (foreign key).
• Create and run a seed file to seed your new battles table.
• Have fun storming the castle.

Bonus

• Seed your weapons table.