[rails] - Databases and Rails Recap Quiz for Week 2

schneems.md

Week 3 Quiz

1) What does ORM stand for?

Object Relational Mapper

2) What are the four functions of persistent storage? (hint: CRUD)

Create, Read , Update, Delete

3) The result is 'princess bride' what was the query? You can use Ruby (ActiveRecord) or SQL

class User < ActiveRecord::Base

end

    ------------------------------------
    | Users Table                      |
    +----+---------+-------------------+
    | ID | Name    | Movie             |
    |----+---------+-------------------|
    | 1  | Richard | zoolander         |
    |----+---------+-------------------|
    | 2  | Ruby    | princess bride    |
    |----+---------+-------------------|
    | 3  | Chris   | sandlot           |
    +----+---------+-------------------|

4) What type of key does the ID column represent in the Users table above

A) Foreign

B) Primary

C) Public

D) Private

5) MIN is a database function, list one more

6) In Rails we could build a blog. On each blog post we might want comments. We could say that a Post has_many :comments and that a Comment belongs to :post.

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

A post has properties :title, :author_name, and :body, a comment has properties :name & :body. Sketch out a posts table and a comments table including the primary and foreign keys. Use this data:

1) "John" wrote a post titled "I love dogs" with the content "woof", "richard" commented "that was great", susan commented "cats are better"

2) "Sara" wrote a post titled "cars are great" with the content " I think they are", "james" commented  "they are"

Sketch this out so it looks like the users table above

7) Using only Ruby (ActiveRecord) and using the data from the above example, how would we find all the posts that were written by "john".

8) What is the output of the following

puts "hello".class


# => __________________






puts {:bird => 'tweet'}.class


# => ___________________





class Adult
end

class Child < Adult
end

little_richie = Child.new

puts little_richie.class


# => ___________________

Hints:

select, where, count, from, *, =