Class: M4DBI::Collection

Inherits:
Object show all
Defined in:
lib/m4dbi/collection.rb

Instance Method Summary collapse

Constructor Details

#initialize(the_one, the_many_model, the_one_fk) ⇒ Collection

Returns a new instance of Collection.



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# File 'lib/m4dbi/collection.rb', line 3

def initialize( the_one, the_many_model, the_one_fk )
  @the_one = the_one
  @the_many_model = the_many_model
  @the_one_fk = the_one_fk
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &blk) ⇒ Object 



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# File 'lib/m4dbi/collection.rb', line 14

def method_missing( method, *args, &blk )
  elements.send( method, *args, &blk )
end

Instance Method Details

#clear ⇒ Object

Returns the number of records deleted



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# File 'lib/m4dbi/collection.rb', line 62

def clear
  stm = @the_many_model.dbh.prepare(
    %{
      DELETE FROM #{@the_many_model.table}
      WHERE #{@the_one_fk} = ?
    }
  )
  stm.execute( @the_one.pk ).affected_count
end

#delete(arg) ⇒ Object 



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# File 'lib/m4dbi/collection.rb', line 25

def delete( arg )
  case arg
    when @the_many_model
      stm = @the_many_model.dbh.prepare(
        %{
          DELETE FROM #{@the_many_model.table}
          WHERE
            #{@the_one_fk} = ?
            AND #{@the_many_model.pk_clause}
        }
      )
      stm.execute(
        @the_one.pk,
        arg.pk
      ).affected_count > 0
    when Hash
      hash = arg
      keys = hash.keys
      where_subclause = keys.map { |k|
        "#{k} = ?"
      }.join( " AND " )
      stm = @the_many_model.dbh.prepare(
        %{
          DELETE FROM #{@the_many_model.table}
          WHERE
            #{@the_one_fk} = ?
            AND #{where_subclause}
        }
      )
      stm.execute(
        @the_one.pk,
        *( keys.map { |k| hash[ k ] } )
      ).affected_count
  end
end

#elements ⇒ Object Also known as: copy 



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# File 'lib/m4dbi/collection.rb', line 9

def elements
  @the_many_model.where( @the_one_fk => @the_one.pk )
end

#push(new_item_hash) ⇒ Object Also known as: <<, add 



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# File 'lib/m4dbi/collection.rb', line 18

def push( new_item_hash )
  new_item_hash[ @the_one_fk ] = @the_one.pk
  @the_many_model.create( new_item_hash )
end