Class: ActiveRecord::PredicateBuilder

Inherits:
Object
  • Object
show all
Defined in:
activerecord/lib/active_record/relation/predicate_builder.rb,
activerecord/lib/active_record/relation/predicate_builder/array_handler.rb,
activerecord/lib/active_record/relation/predicate_builder/relation_handler.rb

Overview

:nodoc:

Defined Under Namespace

Classes: ArrayHandler, RelationHandler

Class Method Summary collapse

Class Method Details

.build_from_hash(klass, attributes, default_table) ⇒ Object


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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 18

def self.build_from_hash(klass, attributes, default_table)
  queries = []

  attributes.each do |column, value|
    table = default_table

    if value.is_a?(Hash)
      if value.empty?
        queries << '1=0'
      else
        table       = Arel::Table.new(column, default_table.engine)
        association = klass._reflect_on_association(column.to_sym)

        value.each do |k, v|
          queries.concat expand(association && association.klass, table, k, v)
        end
      end
    else
      column = column.to_s

      if column.include?('.')
        table_name, column = column.split('.', 2)
        table = Arel::Table.new(table_name, default_table.engine)
      end

      queries.concat expand(klass, table, column, value)
    end
  end

  queries
end

.expand(klass, table, column, value) ⇒ Object


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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 50

def self.expand(klass, table, column, value)
  queries = []

  # Find the foreign key when using queries such as:
  # Post.where(author: author)
  #
  # For polymorphic relationships, find the foreign key and type:
  # PriceEstimate.where(estimate_of: treasure)
  if klass && reflection = klass._reflect_on_association(column.to_sym)
    if reflection.polymorphic? && base_class = polymorphic_base_class_from_value(value)
      queries << build(table[reflection.foreign_type], base_class)
    end

    column = reflection.foreign_key
  end

  queries << build(table[column], value)
  queries
end

.polymorphic_base_class_from_value(value) ⇒ Object


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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 70

def self.polymorphic_base_class_from_value(value)
  case value
  when Relation
    value.klass.base_class
  when Array
    val = value.compact.first
    val.class.base_class if val.is_a?(Base)
  when Base
    value.class.base_class
  end
end

.references(attributes) ⇒ Object


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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 82

def self.references(attributes)
  attributes.map do |key, value|
    if value.is_a?(Hash)
      key
    else
      key = key.to_s
      key.split('.').first if key.include?('.')
    end
  end.compact
end

.register_handler(klass, handler) ⇒ Object

Define how a class is converted to Arel nodes when passed to where. The handler can be any object that responds to call, and will be used for any value that === the class given. For example:

MyCustomDateRange = Struct.new(:start, :end)
handler = proc do |column, range|
  Arel::Nodes::Between.new(column,
    Arel::Nodes::And.new([range.start, range.end])
  )
end
ActiveRecord::PredicateBuilder.register_handler(MyCustomDateRange, handler)

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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 104

def self.register_handler(klass, handler)
  @handlers.unshift([klass, handler])
end

.resolve_column_aliases(klass, hash) ⇒ Object


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# File 'activerecord/lib/active_record/relation/predicate_builder.rb', line 8

def self.resolve_column_aliases(klass, hash)
  hash = hash.dup
  hash.keys.grep(Symbol) do |key|
    if klass.attribute_alias? key
      hash[klass.attribute_alias(key)] = hash.delete key
    end
  end
  hash
end