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
@engine = engine[:engine] if Hash === engine
@columns = nil
@aliases = []
@table_alias = nil
# 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] if Hash === engine
end
def alias
Nodes::TableAlias.new("#{name}_2", self).tap do |node|
@aliases << node
end
end
def tm
SelectManager.new(@engine).from(self)
end
def from table
SelectManager.new(@engine).from 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 ||= @engine.connection.columns(@name, "#{@name} Columns").map do |column|
Attributes.for(column).new self, column.name.to_sym, column
end
end
def [] name
name = name.to_sym
columns.find { |column| column.name == name }
end
end
end