DataORM

About

DataORM is an object relational mapping framework inspired by Active Record. It creates a simple to use interface by forming a connection with the database and abstracting away SQL tables into classes and complex queries into methods.

Instructions

To check out the Pokemon database demo,

• bundle install
• run pry and then load 'pokemon.rb'

To use DataORM in your projects, require the file 'dataORM.rb' and extend SQLObject onto your model.

Methods

• all - returns everything from the table

def self.all 
   results = DBConnection.execute(<<-SQL)
      SELECT
        *
      FROM
        #{self.table_name}
   SQL
   self.parse_all(results)
end 

• find - returns the object with the ID

   def self.find(id)
      result = DBConnection.execute(<<-SQL, id)
         SELECT
         *
         FROM
         #{self.table_name}
         WHERE
         #{self.table_name}.id = ?
      SQL

      parse_all(result).first
   end

• where - parses into correct SQL syntax and returns results from specific WHERE parameters

   def where(params)
      where_line = params.map do |k, v|
         if v.is_a?(String)
         v = "'#{v}'"
         end
         "#{k.to_s} = #{v}"
      end.join(" AND ")

      result = DBConnection.execute(<<-SQL)
         SELECT
            *
         FROM
            #{self.table_name}
         WHERE
            #{where_line}
      SQL

      result.map {|attributes| self.new(attributes)}
   end

• insert - inserts new row into SQL database
• update - updates the object into SQL database

Associations

• belongs_to - creates an association between two tables with the BelongsTo class

   def belongs_to(name, options = {})
      self.assoc_options[name] = BelongsToOptions.new(name, options)

      define_method(name) do 
         options = self.class.assoc_options[name]
         value = self.send(options.foreign_key)
         options.model_class.where(options.primary_key => value).first
      end
   end

• has_many - creates an association between two tables with the HasMany class

   def has_many(name, options = {})
      self.assoc_options[name] = HasManyOptions.new(name, self.name, options)

      define_method(name) do 
         options = self.class.assoc_options[name]
         value = self.send(options.primary_key)
         options.model_class.where(options.foreign_key => value)
      end
   end