Ruby
You need to include the following libraries in your Gemfile:
gem 'pg' #postgresql
gem "sinatra-activerecord" #activerecord orm
In your application file, you need to establish a connection to your database using ActiveRecord. We do so by calling the establish_connection method that ActiveRecord provides. We'll pass in the following arguments:
:adapter => "postgresql":database => "your_db_name_here"That's it! From here on out, you can query and modify the database with ease!
CRUD stands for 'create', 'read', 'update' and 'destroy'. You perform these actions on tables inside of your database. Let's imagine that you have the following SQL table named Sms:
id | message | sender
-------------------------------------------------
1 | "Hi there!" | "Kathew"
2 | "sup man." | "Lichard"
3 | "Just learned Rails!" | "Kathew"
4 | "hey you guys!" | "Cecelious"
sms = Sms.new # create a new
sms.message = "Hi there!" # add values
sms.sender = "Kathew"
sms.save # saves to the database
Hash
obj = { id: 3, message: 'Hi there!', sender: 'Kathew' }
Accessing values via symbols
obj[:message]
# => 'Hi there!'
obj[:message] + " (sent from " + obj[:sender] + ")"
# => "Hi there! (sent from Kathew)"
Find an object in a list of objects
sms = Sms.find(2) # find by id
# => sms = { id: 2, message: "sup man.", sender: "Lichard" }
sms.message
# => "sup man."
sms[:message]
# => "sup man."
sms = Sms.find(4) # find by id
sms.sender = "sms ninja" # update a value
sms.save # save to database
sms = Sms.find(1) # find by id
sms.destroy # delete from database