Class: Prequel::Relations::Selection

Inherits:
Relation
  • Object
show all
Defined in:
lib/prequel/relations/selection.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Relation

#find, #get_column, #join, #project, #query, #singular_table_ref, #table_ref, #to_relation, #where

Constructor Details

#initialize(operand, predicate) ⇒ Selection

Returns a new instance of Selection.



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# File 'lib/prequel/relations/selection.rb', line 6

def initialize(operand, predicate)
  @operand = operand
  @predicate = resolve(predicate.to_predicate)
end

Instance Attribute Details

#operand ⇒ Object (readonly)

Returns the value of attribute operand.



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# File 'lib/prequel/relations/selection.rb', line 4

def operand
  @operand
end

#predicate ⇒ Object (readonly)

Returns the value of attribute predicate.



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# File 'lib/prequel/relations/selection.rb', line 4

def predicate
  @predicate
end

Instance Method Details

#columns ⇒ Object 



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# File 'lib/prequel/relations/selection.rb', line 13

def columns
  operand.columns.map do |column|
    derive(column)
  end
end

#visit(query) ⇒ Object 



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# File 'lib/prequel/relations/selection.rb', line 19

def visit(query)
  operand.visit(query)
  query.add_condition(predicate.resolve_in_query(query))
end