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|
module Arel
module Relation
include Enumerable
@@connection_tables_primary_keys = {}
attr_reader :count
def session
Session.instance
end
def join?
false
end
def call
engine.read(self)
end
def bind(relation)
self
end
def externalize
@externalized ||= externalizable?? Externalization.new(self) : self
end
def externalizable?
false
end
def compiler
@compiler ||= begin
Arel::SqlCompiler.const_get("#{engine.adapter_name}Compiler").new(self)
rescue
Arel::SqlCompiler::GenericCompiler.new(self)
end
end
def to_sql(formatter = nil)
sql = compiler.select_sql
return sql unless formatter
formatter.select sql, self
end
def christener
@christener ||= Sql::Christener.new
end
def inclusion_predicate_sql
"IN"
end
def exclusion_predicate_sql
"NOT IN"
end
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
def select_clauses
attributes.map { |a|
case a
when Value
a.value
else
a.to_sql(Sql::SelectClause.new(self))
end
}
end
def from_clauses
sources.empty? ? table_sql : sources
end
def where_clauses
wheres.collect { |w|
case w
when Value
w.value
else # FIXME: why do we have to pass in a whereclause?
w.to_sql(Sql::WhereClause.new(self))
end
}
end
def group_clauses
groupings.collect { |g| g.to_sql(Sql::GroupClause.new(self)) }
end
def having_clauses
havings.collect { |g| g.to_sql(Sql::HavingClause.new(self)) }
end
def order_clauses
orders.collect { |o| o.to_sql(Sql::OrderClause.new(self)) }
end
def each
session.read(self).each { |e| yield e }
end
module Operable
def join(other_relation = nil, join_class = InnerJoin)
case other_relation
when String
StringJoin.new(self, other_relation)
when Relation
JoinOperation.new(join_class, self, other_relation)
else
self
end
end
def outer_join(other_relation = nil)
join(other_relation, OuterJoin)
end
%w{
having group order project
}.each do |op|
class_eval <<-OPERATION, __FILE__, __LINE__
def #{op}(*args)
args.all? { |x| x.blank? } ? self : #{op.capitalize}.new(self, args)
end
OPERATION
end
def where clause = nil
clause ? Where.new(self, [clause]) : self
end
def skip thing = nil
thing ? Skip.new(self, thing) : self
end
def take thing
Take.new self, thing
end
def from thing
From.new self, thing
end
def lock(locking = nil)
Lock.new(self, locking)
end
def alias
Alias.new(self)
end
def insert(record)
session.create Insert.new(self, record)
end
def update(assignments)
session.update Update.new(self, assignments)
end
def delete
session.delete Deletion.new(self)
end
JoinOperation = Struct.new(:join_class, :relation1, :relation2) do
def on(*predicates)
join_class.new(relation1, relation2, *predicates)
end
end
end
include Operable
def [](index)
attributes[index]
end
def find_attribute_matching_name(name)
attributes.detect { |a| a.named?(name) } || Attribute.new(self, name)
end
def find_attribute_matching_attribute(attribute)
matching_attributes(attribute).max do |a1, a2|
(a1.original_attribute / attribute) <=> (a2.original_attribute / attribute)
end
end
def position_of(attribute)
@position_of ||= {}
return @position_of[attribute] if @position_of.key? attribute
@position_of[attribute] = attributes.index(attributes[attribute])
end
private
def matching_attributes(attribute)
(@matching_attributes ||= attributes.inject({}) do |hash, a|
(hash[a.is_a?(Value) ? a.value : a.root] ||= []) << a
hash
end)[attribute.root] || []
end
def has_attribute?(attribute)
!matching_attributes(attribute).empty?
end
module DefaultOperations
def attributes; Header.new end
def projections; [] end
def wheres; [] end
def orders; [] end
def inserts; [] end
def groupings; [] end
def havings; [] end
def joins(formatter = nil); nil end # FIXME
def taken; nil end
def skipped; nil end
def sources; [] end
def locked; [] end
end
include DefaultOperations
end
end
|
