Active Record Relationships_Assignment 2 Solution

Assignment for Module #2: Active Record Relationships
The overall goal of this assignment is to assess your ability to implement and use Active Record model relationships. This includes:
Creating Active Record models and relationships between the models using a rails-provided generator (rails g model or rails g scaffold) Providing validations for models (using built-in Active Record validations as well as custom validations) Implementing a grandparent relationship with a :through option Providing bootstrap data using a seeds.rb file Implementing default_scope queries Implementing aggregation queries Implementing advanced queries (e.g., SQL snippets) Implementing model/database (DB) cascades
The functional goal of this assignment is to implement relationships and query behavior for the following four (4) model classes
1. User 2. Profile 3. TodoList 4. TodoItem
Functional Requirements
1. Create several Active Record model classes - some of which will have relationships defined when they are created
User Profile TodoList TodoItem
2. Create database migrations for relationships not present when the model classes were created
3. Create a DB schema for each model class and their relationships
4. Populate the DB with bootstrap data
5. Implement relationship features
6. Implement model class features
Getting Started
1. Create a new Rails application called todolists. This will look quite a bit like what you did in the module 1 assignment.
2. Add the following specification to your Gemfile.
group :test do gem 'rspec-rails', '~ 3.0' end
3. Run the bundle command to resolve new gems
4. From the todolists application root directory, initialize the rspec tests using rails generate rspec:install command.
[todolists]$ rails generate rspec:install create .rspec create spec create spec/spec_helper.rb create spec/rails_helper.rb
Add the following line to .rspec to add verbose output to test results.
--format documentation
5. Download and extract the starter set of boostrap files.
|-- Gemfile `-- spec `-- assignment_spec.rb
overwrite your existing Gemfile with the Gemfile from the bootstrap fileset. They should be nearly identical, but this is done to make sure the gems and versions you use in your solution can be processed by the automated Grader when you submit. Any submission should be tested with this version of the file.
add the spec/assignment_spec.rb file provided with the bootstrap fileset to the corresponding spec directory that already exists under your application root directory (e.g., application-rootdirectory/spec/assignment_spec.rb). This file contains tests that will help determine whether you have completed the assignment.
6. Run the rspec test(s) to receive feedback. rspec must be run from the root directory of your application. All tests will (obviously) fail until you complete the specified solution.
$ rspec ... Finished in 0.02831 seconds (files took 1.39 seconds to load) 56 examples, 1 failure, 54 pending
To focus test feedback on a specific step of the requirements, add "-e rq##" to the rspec command line to only evaluate that requirement. Pad all step numbers to two digits.
$ rspec -e rq01 Run options: include {:full_description=/rq01/}
Assignment rq01 Generate Rails application must have top level structure of a rails application
Finished in 0.00356 seconds (files took 1.3 seconds to load) 1 example, 0 failures
$ rspec -e rq02
... Finished in 0.00422 seconds (files took 2.16 seconds to load) 6 examples, 1 failure, 5 pending
Failed examples:
rspec ./spec/assignment_spec.rb:50 # Assignment rq02 User Model: User class created
7. Implement your Models and use the rspec tests to help verify your completed solution.
8. Submit your Rails app solution for grading.
Technical Requirements
1. Create a new Rails app called todolists. Use the Gemfile provided in the boostrap files. Do not change the Gemfile from what is provided or your submitted solution may not be able to be processed by the grader (i.e., do not add any additional gems or change gem versions).
An Entity Relationship (ER) diagram is provided below to help depict each Model's relationship:
|------| 1 1 |----------| | User |----------| Profile | |------| |----------|
\ \ \ 1 * |----------| 1 * |----------| \------| TodoList |----------| TodoItem | |----------| |----------|
2. Re-use the User model class and database table creation commands implemented in Assignment 1. (i.e., you may re-use the exact rails generate command you used to generate this class from the previous assignment)
User
username - a string to hold account identity password_digest - a string to hold password information
Reminder: Ruby/Rails conventions are that class names are CamelCase and file and method names are snake_case.
You must migrate the database schema at this time and in between each of the following steps to be able to pass the rspec tests incrementally.
$ rake db:migrate $ rspec -e rq02 Run options: include {:full_description=/rq02/}
Assignment rq02 User Model: User class created User database structure in place User class properties added should respond to #username should respond to #password_digest should respond to #created_at should respond to #updated_at
Finished in 0.19157 seconds (files took 1.27 seconds to load) 6 examples, 0 failures
3. Re-use the Profile model class and database table creation commands implemented in Assignment 1, except this time create it with a reference to User when you create the model class. The grader will look for the relationship to be included in the initial create table migration for this model class.
Profile
gender - a string to hold the words "male" or "female" birth_year - a number to hold the year the individual was born first_name - a string with given name of user last_name - a string with family name of user user - a 1:1 relationship with User (i.e., Profile belongs_to User)
Also define the 1:1 has_one relationship in the User model class.
User
profile - a 1:1 relationship with Profile (i.e., User has_one profile). Add appropriate options to have the User model class delete a Profile in a cascading fashion
Reminder: Relationships are only generated or migrated in the class forming the relationship (e.g., the many-side of a many:1). The inverse side of a relationship (e.g., the one-side of a 1:many) need only have the relationship declared in the model class and not in the database migration. In this case, Profile is forming the relationship in the database and User is the inverse side.
$ rake db:migrate $ rspec -e rq03
4. Re-use the TodoList model class implemented in Assignment 1 (i.e., you may re-use the exact rails generate command you used to generate this class from the previous assignment). The grader will look for no relations in the initial create table migration for this model class.
TodoList
list_name - a string name assigned to the list list_due_date - a date when todo items in the list are to be complete. This is a date. We are not concerned with the time of day.
$ rake db:migrate $ rspec -e rq04
5. Create a database migration (hint: rails g migration) that adds a database reference from the TodoLists table to the Users table. The grader will look for this relationship to be formed by a database table migration.
Also define the many:1 belongs_to relationship in the TodoList model class.
TodoList
user - a many:1 relationship with User (i.e., TodoList belongs_to User)
Also define the 1:many has_many relationship in the User model class.
User
todo_lists - a 1:many relationship with TodoList (i.e., User has_many todo_lists). Add appropriate options to have the User model class delete a TodoList in a cascading fashion
$ rake db:migrate $ rspec -e rq05
6. Re-use the TodoItem model class implemented in Assignment 1, except this time create it with a many:1 belongs_to relationship with TodoList when you create the model class. The grader will look for the relationship to be included in the initial create table migration for this model class.
TodoItem
due_date - date when the specific task is to be complete title - a string with short name for specific task description - a text field with narrative text for specific task completed - a boolean value (default=false), indicating whether item is complete todo_list - a many:1 relationship with TodoList - TodoItem belongs_to TodoList
Also define the 1:many has_many relationship in the TodoList model class.
TodoList
todo_items - a 1:many relationship with TodoItem (i.e., TodoList has_many todo_items). Add appropriate options to have the TodoList model class delete a TodoItem in a cascading fashion
$ rake db:migrate $ rspec -e rq06
7. Migrate all database schema changes at this time if you have not yet done so. At this point you should have:
four (4) create table (Users, Profiles, TodoLists, and TodoItems) one (1) update table migrations to add reference (TodoLists to Users)
$ rake db:migrate $ rspec -e rq07
8. Implement a 1:many :through relationship from User to TodoItem by using the 1:many relationship from User to TodoLists as a source.
User
todo_items - a 1:many through relationship with TodoItem through TodoLists (i.e., User has_many todo_items)
$ rspec -e rq08
9. Create a seeds.rb file that will clear the existing data from the model tables and load the database with
The four users below with their birth years:
Carly Fiorina, 1954 Donald Trump, 1946 Ben Carson, 1951 Hillary Clinton, 1947
Usernames (e.g., their last names) and a password for each User A Profile for each User Exactly one TodoList per User that is due one year from the date the database is loaded
(hint: Date.today provides today's date and 1.year can be used to define one year)
Each TodoList contains five (5) TodoItems (there must be 20 total) Each TodoItem having a due date of one year from the time the database is loaded Each TodoItem must have an arbitrary title and descriptions
(Hint: you may want to consider using loops)
Once the seeds.rb file is created, populate the database using rake db:seed
$ rake db:seed $ rspec -e rq09
10. Add default_scope to both TodoList and TodoItem models to always return collectons from the database ordered by due dates with earliest dates first.
$ rspec -e rq10
11. Add validation to User and Profile models
User
Define a validation for username to enforce that username be supplied by using a built-in validator
Profile
Define custom validator that permits first_name or last_name to be null but not both Define a validation for gender to be either "male" or "female" by using a built-in validator Define custom validator that prevents anyone that is male (gender) from having the first_name "Sue" ;)
$ rspec -e rq11
12. Add a cascade of deletes that will remove Profile, TodoList, and TodoItem rows for any User removed.
$ rspec -e rq12
13. Add a method to the User model class called get_completed_count, which:
determines the number of TodoItems the User has completed using an aggregate query function
(Hint: You are looking for the count of TodoItems associated with a specific User where completed:true)
returns the count
$ rspec -e rq13
14. Add a class method to the Profile class, called get_all_profiles, which:
accepts a min and max for the birth year issues a BETWEEN SQL clause in a where clause to locate Profiles with birth years that are between min year and max year defends itself against SQL injection when applying the parameters to the SQL clauses returns a collection of Profiles in ASC birth year order
$ rspec -e rq14
Self Grading/Feedback
Some unit tests have been provided in the bootstrap files and provide examples of tests the grader will be evaluating for when you submit your solution. They must be run from the project root directory.
$ rspec ... Finished in 9.56 seconds (files took 1.41 seconds to load) 56 examples, 0 failures
You can run as many specific tests you wish be adding -e rq## -e rq##
$ rspec -e rq01 -e rq02
Submission
Submit an .zip archive (other archive forms not currently supported) with your solution root directory as the top-level (e.g., your Gemfile and sibling files must be in the root of the archive and not in a sub-folder. The grader will replace the spec files with fresh copies and will perform a test with different query terms.
|-- app | |-- assets | |-- controllers | |-- helpers | |-- mailers | |-- models | `-- views |-- bin |-- config |-- config.ru |-- db |-- Gemfile |-- Gemfile.lock |-- lib |-- log |-- public |-- Rakefile |-- README.rdoc |-- test `-- vendor