Hacktive Record

In this lab you will learn how to create seed data and use a simplified ORM dubbed "HacktiveRecord" (a pun on "ActiveRecord" which you'll be using in Rails). We will be working with the FFaker gem and modeling our data using classes and inheritance.

1. Hello World

When you run ruby 1_hello.rb you should see the following printed to your terminal:

"Hello, my name is Generic Student and I live at 123 Rudimentary Dr, Oakland California. I lurv geraniums!"

Modify the output to use string interpolation, and your own name, address, and most favoritest thing in teh world.

Bonus: print it ten times.

2. Motivational Speakers

When you run ruby 2_speakers.rb you should see 10 lines of output, formatted like so:

Reichel Theresia, [email protected], 415-253-3253
Botsford Vicenta, [email protected], 716-282-1443
Waters Nayeli, [email protected], 415-793-2549
...

This output should NOT be hardcoded. It should change for every run of the file!

To achieve this goal, you will need to familiarize yourself with the ffaker gem.

First, install the gems in your Gemfile. Simply run:

bundle install
#or just
bundle

You can also install gems individually (e.g. gem install ffaker), but bundle is better in this case.

Now dive into FFaker's Documentation!

####Pro Tip: Requiring Gems & the Ruby Console You're probably asking yourself, "how can I play with this ffaker data?". Why, in the Ruby Console of course!

To launch the REPL, type:

irb
# or
pry

Then require the ffaker gem in the REPL:

require 'ffaker'
# your code here

But wait! We get all that for free if we just run:

bundle console
# when we get to Rails, we'll use:
rails console

This will launch the Ruby REPL AND require all the gems in our Gemfile.

For more info about bundler, try running bundle --help.

3. Motivational Talks

Printing to the terminal is all very nice, but we want to actually be able to play with the data. Let's convert our talks into objects. When you run 3_talks_data.rb you should see something along the lines of:

Speakers:
{first: "Reichel", last: "Theresia", email: "[email protected]"}
{first: "Botsford", last: "Vicenta", email: "[email protected]"}
{first: "Waters", last: "Nayeli", email: "[email protected]"}
...

Talks:
{topic: "Organized secondary matrices", duration: 30}
{topic: "Networked incremental focus group", duration: 45}
{topic: "Optional cohesive middleware", duration: 60}
...

4. Model Speakers

Now let's take it up a notch. Instead of printing out objects, let's print out instances of class Speaker. When I run ruby 4_model_speakers.rb, I expect to see the guts of our objects printed out like this:

#<Speaker:0x007fa86225cfa8 @first_name="Herman", @last_name="Delia", @email="[email protected]", @id=1>
#<Speaker:0x007fa86225cc60 @first_name="Kessler", @last_name="George", @email="[email protected]", @id=2>

You'll need to modify the code in models/speaker.rb so that you can do something like this in 4_model_speakers.rb:

puts Speaker.new({first: "Reichel", last: "Theresia", email: "[email protected]"})

5. Hacktive Record

Now we're going to play with a super-simplified version of Active Record I've dubbed "HacktiveRecord". HacktiveRecord will give our models the ability to save, create and find all records (or "instances") of our class.

Let's start by modifying our Speaker class so that it inherits from HacktiveRecord::Base.

require "./hacktive_record.rb"
class Speaker << HacktiveRecord::Base
end

Now, we have two options for saving our instances.

reichel = Speaker.new({first: "Reichel", last: "Theresia", email: "[email protected]"})
reichel.save

or

reichel = Speaker.create({first: "Reichel", last: "Theresia", email: "[email protected]"})

We can also query for all the records in our pretend "database":

puts Speaker.all

Stretch: Can you model both a Speaker and a Talk object, using our simplified HacktiveRecord? (Hint: you may need to specify speaker_id on your talk objects so you know who they belong to!)

#Ready for Rails! This has been a very light introduction to faking data, seeding your database, and working with models and inheritance. We're ready to dive into rails and work with ActiveRecord!

####1. Create a new rails application Make sure you're in a new project folder

rails new conference_app -T -d postgresql
cd conference_app
bundle
git init
git add . -A
git commit -m "inital commit, rails skeleton"
subl .

####2. Create a Talk model

rails g model talk topic:string duration:integer
git diff # take a look at the files you just created!

And take a look at the following files:

• app/models/talk.rb
• db/migrate/1234566789_create_talks.rb

####3. Setup your database Download and Launch Postgres.app. You should see an elephant in your menu if it's running.

Next, create your application database:

rake db:create # create a new database on your machine
rake db:migrate # instruct your database what tables it needs to contain

####4. Launch the rails console and create your first talk!

rails console
# or
rails c

Confirm that your model exists

Talk
 #=> Talk(id: integer, topic: string, duration: integer, created_at: datetime, updated_at: datetime) 

(You may need to "connect" to your database in the rails console. Just follow the instructions.)

Create your first record!

Talk.create({topic: "Playing with Models in the Rails Console"})
Talk.count
Talk.all

Try the following:

• Create 3 new Talks in the Rails Console.
• Delete the last talk you created
• Find the first talk
• Find the last talk
• Search by id
• Search by title
• Sort by title
• Update the title of the last talk you created
• Delete all the talks you created.

Pro-Tip: Remember, when you're working in the console/repl up-arrow is your friend! (That and "hanging a dot" + "double-tabbing").

####5. Can you seed your database? Take a look at db/seed.rb.

Add the following line:

p "Hello from seed.rb"

Now run the following from your command line (not the console!):

rake db:seed
# Hello from seed.rb

The seed.rb file is magic, because it already knows about all of the models and gems in your rails app. All you have to do is tell it what data to create!

Can you seed your database with speaker and talks?

Bonus: can you do it with the FFaker gem?