Module: Arel::Relation

Includes:
AttributeAccessable, DefaultOperations, Enumerable, Operable
Included in:
Array, Compound, Join, Nil, Table
Defined in:
lib/arel/algebra/relations/relation.rb,
lib/arel/engines/sql/relations/relation.rb,
lib/arel/algebra/relations/operations/join.rb,
lib/arel/algebra/relations/utilities/externalization.rb

Defined Under Namespace

Modules: AttributeAccessable, DefaultOperations, Enumerable, Operable

Constant Summary collapse

@@connection_tables_primary_keys = 
{}

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from DefaultOperations

#attributes, #groupings, #havings, #inserts, #joins, #locked, #orders, #projections, #skipped, #sources, #taken, #wheres

Methods included from AttributeAccessable

#[], #find_attribute_matching_attribute, #find_attribute_matching_name, #position_of

Methods included from Operable

#alias, #join, #lock, #outer_join

Methods included from Operable::Writable

#delete, #insert, #update

Methods included from Enumerable

#each, #first

Instance Attribute Details

#count ⇒ Object (readonly)

Returns the value of attribute count.



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# File 'lib/arel/algebra/relations/relation.rb', line 3

def count
  @count
end

Instance Method Details

#bind(relation) ⇒ Object 



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# File 'lib/arel/algebra/relations/relation.rb', line 13

def bind(relation)
  self
end

#call ⇒ Object 



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# File 'lib/arel/algebra/relations/relation.rb', line 9

def call
  engine.read(self)
end

#christener ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 17

def christener
  @christener ||= Sql::Christener.new
end

#compiler ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 5

def compiler
  @compiler ||=  begin
    "Arel::SqlCompiler::#{engine.adapter_name}Compiler".constantize.new(self)
  rescue
    Arel::SqlCompiler::GenericCompiler.new(self)
  end
end

#exclusion_predicate_sql ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 25

def exclusion_predicate_sql
  "NOT IN"
end

#externalizable? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arel/algebra/relations/utilities/externalization.rb', line 20

def externalizable?
  false
end

#externalize ⇒ Object 



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# File 'lib/arel/algebra/relations/utilities/externalization.rb', line 16

def externalize
  @externalized ||= externalizable?? Externalization.new(self) : self
end

#inclusion_predicate_sql ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 21

def inclusion_predicate_sql
  "IN"
end

#join? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arel/algebra/relations/operations/join.rb', line 65

def join?
  false
end

#primary_key ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 29

def primary_key
  connection_id = engine.connection.object_id
  if @@connection_tables_primary_keys[connection_id] && @@connection_tables_primary_keys[connection_id].has_key?(table.name)
    @@connection_tables_primary_keys[connection_id][table.name]
  else
    @@connection_tables_primary_keys[connection_id] ||= {}
    @@connection_tables_primary_keys[connection_id][table.name] = engine.connection.primary_key(table.name)
  end
end

#session ⇒ Object 



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# File 'lib/arel/algebra/relations/relation.rb', line 5

def session
  Session.new
end

#to_sql(formatter = Sql::SelectStatement.new(self)) ⇒ Object 



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# File 'lib/arel/engines/sql/relations/relation.rb', line 13

def to_sql(formatter = Sql::SelectStatement.new(self))
  formatter.select compiler.select_sql, self
end