Class: CommaHeaven::Sqler::HasManyColumns

Inherits:
AssociationColumns show all
Defined in:
lib/comma-heaven/sqler/has_many_columns.rb

Instance Attribute Summary

Attributes inherited from AssociationColumns

#association, #position

Attributes inherited from Columns

#index, #model, #options, #parent

Instance Method Summary collapse

Methods inherited from AssociationColumns

#foreign_key_for, #initialize, #prefix, #table_alias

Methods inherited from Columns

#initialize, #joins, #prefix, #select, #sql_as, #table, #table_alias

Constructor Details

This class inherits a constructor from CommaHeaven::Sqler::AssociationColumns

Instance Method Details

#join_clause ⇒ Object 



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# File 'lib/comma-heaven/sqler/has_many_columns.rb', line 4

def join_clause
  # @:through@ relantionships requires special treatment: 
  # the JOIN must walk through 2 table 
  join = if association.options[:through]
    <<-EOS
      LEFT JOIN #{association.through_reflection.table_name} AS _#{association.through_reflection.table_name}#{table_alias}
        ON #{parent.table_alias}.#{model.primary_key} = _#{association.through_reflection.table_name}#{table_alias}.#{foreign_key_for(association.through_reflection)}
      LEFT JOIN #{quote(table)} AS #{table_alias}
        ON _#{association.through_reflection.table_name}#{table_alias}.#{model.primary_key} = #{table_alias}.#{association.through_reflection.association_foreign_key}
    EOS
  else
    <<-EOS
      LEFT JOIN #{quote(table)} AS #{table_alias}
        ON #{parent.table_alias}.#{model.primary_key} = #{table_alias}.#{foreign_key_for(association)}
    EOS
  end

  unless options[:by] == 'row'
    join += ' ' + if association.options[:through]
      <<-EOS
        AND #{table_alias}.#{association.klass.primary_key} = 
          ( SELECT #{association.quoted_table_name}.#{association.klass.primary_key} 
            FROM #{association.quoted_table_name} 
            JOIN #{association.through_reflection.table_name} ON #{association.quoted_table_name}.#{association.through_reflection.association_foreign_key} = #{association.through_reflection.table_name}.#{association.through_reflection.klass.primary_key}
            WHERE #{foreign_key_for(association.through_reflection)} = #{parent.table_alias}.#{model.primary_key} 
            LIMIT #{index}, 1 )
      EOS
    else
      <<-EOS
        AND #{table_alias}.#{association.klass.primary_key} = (SELECT #{association.klass.primary_key} FROM #{association.quoted_table_name} WHERE #{foreign_key_for(association)} = #{parent.table_alias}.#{model.primary_key} LIMIT #{index}, 1)
      EOS
    end
  end

  join
end