post_challenge.md

Post challenge

Sorry about the ambiguity for the morning challenge yesterday. Hopefully these instructions clear a few things up for people.

Instructions

Firstly, run the posts_spec.rb file to insert data into the posts_spec.db database. Use sqlite3 .schema to ensure you have a table in there.

# CREATE TABLE `posts`
#  `id`  INTEGER PRIMARY KEY AUTOINCREMENT,
#  `title` TEXT,
#  `url` TEXT,
#  `votes`  INTEGER

Now go into your post.rb file.

require 'sqlite3'
DB = SQLite3::Database.new("posts_spec.db")

posts = DB.execute("""
    SELECT *
    FROM posts
    """)
p posts

This code allows you to run SQL in ruby. Posts is an array of posts. Comment out this section when you understand what it's doing.

class Post 
    def initialize(attributes = {})
        # code 
    end

Add an initialize method to store instance variables from the posts table defined above. Use an attributes hash as an argument.

def self.find(id) 
    # DB.execute( SQL code )
    # once you have this working you need to create a new post instance 
    # Post.new(attributes)   
end 

Implement a class method find(id) on the Post class which takes an integer as an argument (the post id) and will return an instance of Post.

def self.all
    # DB.execute( SQL code )
    # once you have this working you need to create a new post instances
    # Post.new(attributes) 
end 

Implement a class method all on the Post class which takes no argument and will return an array of Post instances.

In the end I want you to have a separate file post_test.rb that looks like this.

require_relative 'post.rb'

Post.find(2)
=> return the instance 

Post.all
=> return all instances 

Part two

Continue on with this challenge and implement ‘destroy’ and ‘save’ instance methods. Think about why these need to be instance methods instead of the class methods we have already made.

This is what I want you to be able to do in your post_test.rb file.

post = Post.new(title: "Awesome article")
post.id
# => nil (the post is not persisted yet)
post.save  # todo: persist the record!
post.id
# => 6 (expected result, the database has inserted a row, store the id in memory)
post.title = "Awesome article, updated"
post.save   # todo: should update the record in the database
post.destroy # removes the post from the database