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

Start by cloning this project.

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 (hint: #{first_name}), and your own name, address, and most favoritest thing in the world.

Bonus: print it ten times.

2. Motivational Speakers

Modify 2_speakers.rb so that when you run ruby 2_speakers.rd you see 10 lines of output, formatted like so:

Reichel Theresia, giovani@gmail.com, 415-253-3253
Botsford Vicenta, ernestine@gmail.com, 716-282-1443
Waters Nayeli, annabel_walter@gmail.com, 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!

3. Motivational Talks

Let's convert our talks into objects. Modify 3_talks_data.rb so that when you run it you see something along the lines of:

Speakers
========
{:first_name=>"Joanny", :last_name=>"McGlynn", :email=>"rex_walsh@gmail.com", :phone=>"530-978-7619"}
{:first_name=>"Cordelia", :last_name=>"Olson", :email=>"mervin.wehner@gmail.com", :phone=>"357-304-4194"}
{:first_name=>"Benjamin", :last_name=>"Bashirian", :email=>"eusebio_gibson@gmail.com", :phone=>"474-759-7334"}
...

Talks
========
{:topic=>"Assimilated object-oriented moderator", :duration=>75}
{:topic=>"Balanced fault-tolerant paradigm", :duration=>60}
{:topic=>"Configurable local alliance", :duration=>90}

...

4. Model Speakers

Now let's take it up a notch. Instead of printing out objects, let's print out instances of class Speaker. Modify 4_model_speakers.rb so that when you run ruby 4_model_speakers.rb, you see the guts of our objects printed out like this:

#<Speaker:0x007fa86225cfa8 @first_name="Herman", @last_name="Delia", @email="charlene@yahoo.com", @id=1>
#<Speaker:0x007fa86225cc60 @first_name="Kessler", @last_name="George", @email="bernie@hotmail.com", @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:

speaker = Speaker.new({first: "Reichel", last: "Theresia", email: "giovani@gmail.com"})
p speaker

A note on p vs puts:
puts calls to_s on the object and generally returns a readable version of the object. p is equivalent to puts, but with the inspect method called instead of the to_s. So with p we will see the difference between "2" and 2. This method is better for debugging.

5. Hacktive Record

Now we're going to play with a super-simplified version of Active Record I've dubbed "HacktiveRecord". HacktiveRecord (defined in hacktive_record.rb) 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: "giovani@gmail.com"})
reichel.save

reichel = Speaker.create({first: "Reichel", last: "Theresia", email: "giovani@gmail.com"})

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

p Speaker.all

#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/seeds.rb.

Add the following line:

p "Hello from seeds.rb"

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

rake db:seed
# Hello from seeds.rb

The seeds.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?