Class: Urbix::ActsAsView::ViewRelations

Inherits:
Object
  • Object
show all
Defined in:
lib/urbix/acts_as_view.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model_klass) ⇒ ViewRelations

Returns a new instance of ViewRelations.



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# File 'lib/urbix/acts_as_view.rb', line 11

def initialize(model_klass)
  @klass = model_klass
  @selects = []
  # hash which associate tables to an array of belongs_to relation chain
  # for each belongs_to relations chain this class will genereate a table reference 
  # in from_clause and a join condition in join_clause
  @needed_relations = {}
  # hash wich associate a belongs_to chain to a table_reference
  @table_ref = {}
end

Instance Attribute Details

#klass ⇒ Object (readonly)

Returns the value of attribute klass.



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# File 'lib/urbix/acts_as_view.rb', line 9

def klass
  @klass
end

#needed_relations ⇒ Object (readonly)

Returns the value of attribute needed_relations.



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# File 'lib/urbix/acts_as_view.rb', line 9

def needed_relations
  @needed_relations
end

Instance Method Details

#add(name, belongs_to_list) ⇒ Object 



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# File 'lib/urbix/acts_as_view.rb', line 22

def add(name, belongs_to_list)
  belongs_list = belongs_to_list.dup
  # 1. retrieve column name that is the last element from belongs_rel_list
  col_name = belongs_list.pop
  # 2. get table reference for the complete belongs_to relation chain
  # this action will also add the corresponding relation if needed
  table_ref = ref_bl_list(belongs_list)
  # 3. Build select clause for this relation
  @selects << "#{table_ref}.#{col_name} as #{name}"
  # 4. add all relations required by the belongs_to list
  until belongs_list.empty?
    ref_bl_list(belongs_list) 
    belongs_list.pop
  end
end

#from_clause ⇒ Object 



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# File 'lib/urbix/acts_as_view.rb', line 54

def from_clause
  clause = [klass.table_name]
  @needed_relations.each do |ref_table,v|
    clause << ref_table
    i = 1
    v[1..-1].each{ |bl| clause << "#{ref_table} #{ref_table}_#{i}" ; i+=1 }
  end
  clause.join(', ')
end

#join_clause ⇒ Object 



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# File 'lib/urbix/acts_as_view.rb', line 38

def join_clause
  clause = []
  @needed_relations.each do |ref_table,rel_list|
    rel_list.each do |relation|
       reflection = relation.last
       fk = reflection.foreign_key
       pk = reflection.klass.primary_key
       bl_list = relation[0...-1] + [reflection.name]
       ref_table = @table_ref[relation[0...-1]] || klass.table_name
       bel_table = @table_ref[bl_list]
       clause << "#{ref_table}.#{fk}=#{bel_table}.#{pk}"
    end
  end
  clause.join(" and ")
end

#select_clause ⇒ Object 



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# File 'lib/urbix/acts_as_view.rb', line 64

def select_clause
  @selects.join(', ')
end