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module Arel
class SelectManager < Arel::TreeManager
include Arel::Crud
def initialize engine
super
@head = Nodes::SelectStatement.new
@ctx = @head.cores.last
end
def taken
@head.limit
end
def skip amount
@head.offset = Nodes::Offset.new(amount)
self
end
def where_clauses
warn "where_clauses is deprecated" if $VERBOSE
to_sql = Visitors::ToSql.new @engine
@ctx.wheres.map { |c| to_sql.accept c }
end
def lock locking = true
# FIXME: do we even need to store this? If locking is +false+ shouldn't
# we just remove the node from the AST?
@head.lock = Nodes::Lock.new
self
end
def locked
@head.lock
end
def on *exprs
@ctx.froms.last.constraint = Nodes::On.new(collapse(exprs))
self
end
def group *columns
columns.each do |column|
# FIXME: backwards compat
column = Nodes::SqlLiteral.new(column) if String === column
column = Nodes::SqlLiteral.new(column.to_s) if Symbol === column
@ctx.groups.push Nodes::Group.new column
end
self
end
def from table
if String === table
return self if @ctx.froms.any? { |x| x.name.to_s == table }
end
@ctx.froms << table
self
end
def join relation, klass = Nodes::InnerJoin
return self unless relation
case relation
when String, Nodes::SqlLiteral
raise if relation.blank?
from Nodes::StringJoin.new(@ctx.froms.pop, relation)
else
from klass.new(@ctx.froms.pop, relation, nil)
end
end
def having expr
expr = Nodes::SqlLiteral.new(expr) if String === expr
@ctx.having = Nodes::Having.new(expr)
self
end
def project *projections
# FIXME: converting these to SQLLiterals is probably not good, but
# rails tests require it.
@ctx.projections.concat projections.map { |x|
String == x.class ? SqlLiteral.new(x) : x
}
self
end
def where expr
@ctx.wheres << expr
self
end
def order *expr
# FIXME: We SHOULD NOT be converting these to SqlLiteral automatically
@head.orders.concat expr.map { |x|
String === x || Symbol === x ? Nodes::SqlLiteral.new(x.to_s) : x
}
self
end
def orders
@head.orders
end
def wheres
Compatibility::Wheres.new @engine, @ctx.wheres
end
def take limit
@head.limit = limit
self
end
def join_sql
viz = Visitors::JoinSql.new @engine
Nodes::SqlLiteral.new viz.accept @ctx
end
def order_clauses
Visitors::OrderClauses.new(@engine).accept(@head).map { |x|
Nodes::SqlLiteral.new x
}
end
def joins manager
manager.join_sql
end
def to_a
raise NotImplementedError
end
# FIXME: this method should go away
def insert values
im = InsertManager.new @engine
im.into @ctx.froms.last
im.insert values
@engine.connection.insert im.to_sql
end
private
def collapse exprs
return exprs.first if exprs.length == 1
right = exprs.pop
left = exprs.pop
right = Nodes::And.new left, right
exprs.reverse.inject(right) { |memo,expr| Nodes::And.new(expr, memo) }
end
end
end
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