Implement MyAttrAccessor Class

.rspec

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+--color
+--format documentation

README.md

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+After the project, you can review the solution here:
+
+* https://github.com/appacademy-solutions/active_record_lite/tree/solution

cats.sql

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+CREATE TABLE cats (
+  id INTEGER PRIMARY KEY,
+  name VARCHAR(255) NOT NULL,
+  owner_id INTEGER NOT NULL,
+
+  FOREIGN KEY(owner_id) REFERENCES human(id)
+);
+
+CREATE TABLE humans (
+  id INTEGER PRIMARY KEY,
+  fname VARCHAR(255) NOT NULL,
+  lname VARCHAR(255) NOT NULL,
+  house_id INTEGER NOT NULL,
+
+  FOREIGN KEY(house_id) REFERENCES human(id)
+);
+
+CREATE TABLE houses (
+  id INTEGER PRIMARY KEY,
+  address VARCHAR(255) NOT NULL
+);
+
+INSERT INTO
+  houses (address)
+VALUES
+  ("26th and Guerrero"), ("Dolores and Market");
+
+INSERT INTO
+  humans (fname, lname, house_id)
+VALUES
+  ("Devon", "Watts", 1), ("Matt", "Rubens", 1), ("Ned", "Ruggeri", 2);
+
+INSERT INTO
+  cats (name, owner_id)
+VALUES
+  ("Breakfast", 1), ("Earl", 2), ("Haskell", 3), ("Markov", 3);

lib/active_record_lite/00_attr_accessor_object.rb

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+class AttrAccessorObject
+  def self.my_attr_accessor(*names)
+    names.each do |name|
+      define_method(name) { instance_variable_get("@#{name}") }
+      define_method("#{name}=") { |arg| instance_variable_set("@#{name}", arg) }
+    end
+  end
+end

lib/active_record_lite/01_mass_object.rb

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+# deprecated for Rails 4
+# require_relative '00_attr_accessor_object.rb'
+#
+# class MassObject < AttrAccessorObject
+#   def self.my_attr_accessible(*new_attributes)
+#     # ...
+#   end
+#
+#   def self.attributes
+#     # ...
+#   end
+#
+#   def initialize(params = {})
+#     # ...
+#   end
+# end

lib/active_record_lite/02_sql_object.rb

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+require_relative 'db_connection'
+require_relative '01_mass_object'
+require 'active_support/inflector'
+
+class MassObject
+  def self.parse_all(results)
+    # ...
+  end
+end
+
+class SQLObject < MassObject
+  def self.columns
+    # ...
+  end
+
+  def self.table_name=(table_name)
+    # ...
+  end
+
+  def self.table_name
+    # ...
+  end
+
+  def self.all
+
+  end
+
+  def self.find(id)
+    # ...
+  end
+
+  def attributes
+    # ...
+  end
+
+  def insert
+    # ...
+  end
+
+  def initialize
+    # ...
+  end
+
+  def save
+    # ...
+  end
+
+  def update
+    # ...
+  end
+
+  def attribute_values
+    # ...
+  end
+end

lib/active_record_lite/03_searchable.rb

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+require_relative 'db_connection'
+require_relative '02_sql_object'
+
+module Searchable
+  def where(params)
+    # ...
+  end
+end
+
+class SQLObject
+  # Mixin Searchable here...
+end

lib/active_record_lite/04_associatable.rb

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+require_relative '03_searchable'
+require 'active_support/inflector'
+
+# Phase IVa
+class AssocOptions
+  attr_accessor(
+    :foreign_key,
+    :class_name,
+    :primary_key,
+  )
+
+  def model_class
+    # ...
+  end
+
+  def table_name
+    # ...
+  end
+end
+
+class BelongsToOptions < AssocOptions
+  def initialize(name, options = {})
+    # ...
+  end
+end
+
+class HasManyOptions < AssocOptions
+  def initialize(name, self_class_name, options = {})
+    # ...
+  end
+end
+
+module Associatable
+  # Phase IVb
+  def belongs_to(name, options = {})
+    # ...
+  end
+
+  def has_many(name, options = {})
+    # ...
+  end
+
+  def assoc_options
+    # Wait to implement this in Phase V. Modify `belongs_to`, too.
+  end
+end
+
+class SQLObject
+  # Mixin Associatable here...
+end

lib/active_record_lite/05_associatable2.rb

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+require_relative '04_associatable'
+
+# Phase V
+module Associatable
+  # Remember to go back to 04_associatable to write ::assoc_options
+
+  def has_one_through(name, through_name, source_name)
+    # ...
+  end
+end

lib/active_record_lite/db_connection.rb

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+require 'sqlite3'
+
+# https://tomafro.net/2010/01/tip-relative-paths-with-file-expand-path
+ROOT_FOLDER = File.join(File.dirname(__FILE__), "../..")
+CATS_SQL_FILE = File.join(ROOT_FOLDER, "cats.sql")
+CATS_DB_FILE = File.join(ROOT_FOLDER, "cats.db")
+
+class DBConnection
+  def self.open(db_file_name)
+    @db = SQLite3::Database.new(db_file_name)
+    @db.results_as_hash = true
+    @db.type_translation = true
+
+    @db
+  end
+
+  def self.reset
+    commands = [
+      "rm #{CATS_DB_FILE}",
+      "cat #{CATS_SQL_FILE} | sqlite3 #{CATS_DB_FILE}"
+    ]
+
+    commands.each { |command| `#{command}` }
+    DBConnection.open(CATS_DB_FILE)
+  end
+
+  def self.instance
+    self.reset if @db.nil?
+
+    @db
+  end
+
+  def self.execute(*args)
+    puts args[0]
+
+    self.instance.execute(*args)
+  end
+
+  def self.execute2(*args)
+    puts args[0]
+
+    self.instance.execute2(*args)
+  end
+
+  def self.last_insert_row_id
+    self.instance.last_insert_row_id
+  end
+
+  private
+  def initialize(db_file_name)
+  end
+end

spec/00_attr_accessor_object_spec.rb

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+require 'active_record_lite/00_attr_accessor_object'
+
+describe AttrAccessorObject do
+  before(:all) do
+    class MyAttrAccessorObject < AttrAccessorObject
+      my_attr_accessor :x, :y
+    end
+  end
+
+  subject(:obj) { MyAttrAccessorObject.new }
+
+  it "#my_attr_accessor adds #x and #y" do
+    expect(obj).to respond_to(:x)
+    expect(obj).to respond_to(:y)
+  end
+
+  it "#my_attr_accessor adds #x= and #y=" do
+    expect(obj).to respond_to(:x=)
+    expect(obj).to respond_to(:y=)
+  end
+
+  it "#my_attr_accessor methods really get and set" do
+    obj.x = "xxx"
+    obj.y = "yyy"
+
+    expect(obj.x).to eq("xxx")
+    expect(obj.y).to eq("yyy")
+  end
+end

spec/01_mass_object_spec.rb

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+# deprecated in favor of Rails 4 stuff
+# require 'active_record_lite/01_mass_object'
+#
+# # Use these if you like.
+# describe MassObject do
+#   before(:all) do
+#     class EmptyMassObject < MassObject
+#     end
+#
+#     class MyMassObject < MassObject
+#       my_attr_accessor :x, :y
+#
+#       # removed during upgrade to rails 4
+#       # my_attr_accessible :x, :y
+#     end
+#   end
+#
+#   it "::attributes starts out empty" do
+#     expect(EmptyMassObject.attributes).to be_empty
+#   end
+#
+#   it "::attriburtes cannot be called directly on MassObject" do
+#     expect {
+#       MassObject.attributes
+#     }.to raise_error("must not call #attributes on MassObject directly")
+#   end
+#
+#   # removed during upgrade to rails 4
+#   # it "::my_attr_accessible sets self.attributes" do
+#   #   expect(MyMassObject.attributes).to eq([:x, :y])
+#   # end
+#
+#   it "#initialize performs mass-assignment" do
+#     obj = MyMassObject.new(:x => "xxx", :y => "yyy")
+#
+#     expect(obj.x).to eq("xxx")
+#     expect(obj.y).to eq("yyy")
+#   end
+#
+#   it "#initialize doesn't mind string keys" do
+#     obj = MyMassObject.new("x" => "xxx", "y" => "yyy")
+#
+#     expect(obj.x).to eq("xxx")
+#     expect(obj.y).to eq("yyy")
+#   end
+#
+#
+#   # removed during upgrade to rails 4
+#   # it "#initialize rejects unregistered keys" do
+#   #   expect {
+#   #     obj = MyMassObject.new(:z => "zzz")
+#   #   }.to raise_error("mass assignment to unregistered attribute 'z'")
+#   # end
+# end