Class: Bmg::Sql::Processor::Where

Inherits:
Bmg::Sql::Processor show all
Defined in:
lib/bmg/sql/processor/where.rb

Constant Summary

Constants inherited from Bmg::Sql::Processor

UnexpectedError

Instance Attribute Summary

Attributes inherited from Bmg::Sql::Processor

#builder

Instance Method Summary collapse

Methods inherited from Bmg::Sql::Processor

#on_set_operator, #on_with_exp

Constructor Details

#initialize(predicate, builder) ⇒ Where

Returns a new instance of Where.



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# File 'lib/bmg/sql/processor/where.rb', line 6

def initialize(predicate, builder)
  super(builder)
  @predicate = predicate
end

Instance Method Details

#on_select_exp(sexpr) ⇒ Object 



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# File 'lib/bmg/sql/processor/where.rb', line 22

def on_select_exp(sexpr)
  if sexpr.group_by_clause || sexpr.has_computed_attributes?
    sexpr = builder.from_self(sexpr)
    call(sexpr)
  else
    pred = @predicate.rename(sexpr.desaliaser(true))
    if sexpr.where_clause
      sexpr_p = Predicate.new(sexpr.where_clause.predicate)
      sexpr.with_update(:where_clause, [ :where_clause, (sexpr_p & pred).sexpr ])
    else
      sexpr.with_insert(4, [ :where_clause, pred.sexpr ])
    end
  end
end

#on_union(sexpr) ⇒ Object 



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# File 'lib/bmg/sql/processor/where.rb', line 11

def on_union(sexpr)
  non_falsy = sexpr[2..-1].reject{|expr| falsy?(expr) }
  if non_falsy.empty?
    apply(sexpr.head_expr)
  elsif non_falsy.size == 1
    apply(non_falsy.first)
  else
    [sexpr[0], sexpr[1]] + non_falsy.map{|nf| apply(nf) }
  end
end