module Arel class Table include Arel::Crud @engine = nil class << self; attr_accessor :engine; end attr_reader :name, :engine, :aliases, :table_alias def initialize name, engine = Table.engine @name = name @engine = engine @columns = nil @aliases = [] @table_alias = nil @primary_key = nil if Hash === engine @engine = engine[:engine] || Table.engine @columns = attributes_for engine[:columns] # Sometime AR sends an :as parameter to table, to let the table know # that it is an Alias. We may want to override new, and return a # TableAlias node? @table_alias = engine[:as] unless engine[:as].to_s == name.to_s end end def primary_key @primary_key ||= self[@engine.connection.primary_key(name)] end def alias Nodes::TableAlias.new("#{name}_2", self).tap do |node| @aliases << node end end def tm SelectManager.new(@engine, self) end def from table SelectManager.new(@engine, table) end def joins manager nil end def join relation, klass = Nodes::InnerJoin return tm unless relation sm = SelectManager.new(@engine) case relation when String, Nodes::SqlLiteral raise if relation.blank? sm.from Nodes::StringJoin.new(self, relation) else sm.from klass.new(self, relation, nil) end end def group *columns tm.group(*columns) end def order *expr tm.order(*expr) end def where condition tm.where condition end def project *things tm.project(*things) end def take amount tm.take amount end def having expr tm.having expr end def columns @columns ||= attributes_for @engine.connection.columns(@name, "#{@name} Columns") end def [] name return nil unless table_exists? name = name.to_sym columns.find { |column| column.name == name } end private def attributes_for columns return nil unless columns columns.map do |column| Attributes.for(column).new self, column.name.to_sym, column end end def table_exists? @table_exists ||= tables.key?(@name) || engine.connection.table_exists?(name) end def tables self.class.table_cache(@engine) end @@table_cache = nil def self.table_cache engine # :nodoc: @@table_cache ||= Hash[engine.connection.tables.map { |x| [x,true] }] end end end