class Sequel::Postgres::PGRowOp

  1. lib/sequel/extensions/pg_row_ops.rb
Parent: Postgres

This class represents a composite type expression reference.

Methods

Public Class

  1. wrap

Public Instance

  1. *
  2. []
  3. splat

Constants

CLOSE_DOT = ').'.freeze  
CLOSE_STAR = '.*)'.freeze  
CLOSE_STAR_CAST = '.*)::'.freeze  
EMPTY = "".freeze  
OPEN = '('.freeze  
QUALIFY = [OPEN, CLOSE_DOT].freeze  
ROW = [OPEN, CLOSE_STAR].freeze  
ROW_CAST = [OPEN, CLOSE_STAR_CAST].freeze  
WRAP = [EMPTY].freeze  

Public Class methods

wrap (expr)

Wrap the expression in a PGRowOp, without changing the SQL it would use.

[show source] 
# File lib/sequel/extensions/pg_row_ops.rb, line 98
def self.wrap(expr)
  PGRowOp.new(WRAP, [expr])
end

Public Instance methods

* (ce=(arg=false;nil))

Use the (identifier).* syntax to reference the members of the composite type as separate columns. Generally used when you want to expand the columns of a composite type to be separate columns in the result set.

Sequel.pg_row_op(:a).*     # (a).*
Sequel.pg_row_op(:a)[:b].* # ((a).b).*
[show source] 
# File lib/sequel/extensions/pg_row_ops.rb, line 123
def *(ce=(arg=false;nil))
  if arg == false
    Sequel::SQL::ColumnAll.new([self])
  else
    super(ce)
  end
end
[] (member)

Access a member of the composite type if given a symbol or an SQL::Identifier. For all other access, assuming the pg_array_ops extension is loaded and that it represents an array access. In either case, return a PgRowOp so that access can be cascaded.

[show source] 
# File lib/sequel/extensions/pg_row_ops.rb, line 107
def [](member)
  case member
  when Symbol, SQL::Identifier
    PGRowOp.new(QUALIFY, [self, member])
  else
    PGRowOp.wrap(Sequel.pg_array_op(self)[member])
  end
end
splat (cast_to=nil)

Use the (identifier.*) syntax to indicate that this expression represents the composite type of one of the tables being referenced, if it has the same name as one of the columns. If the cast_to argument is given, also cast the expression to that type (which should be a symbol representing the composite type). This is used if you want to return whole table row as a composite type.

Sequel.pg_row_op(:a).splat[:b] # (a.*).b
Sequel.pg_row_op(:a).splat(:a) # (a.*)::a
[show source] 
# File lib/sequel/extensions/pg_row_ops.rb, line 142
def splat(cast_to=nil)
  if args.length > 1
    raise Error, 'cannot splat a PGRowOp with multiple arguments'
  end

  if cast_to
    PGRowOp.new(ROW_CAST, args + [cast_to])
  else
    PGRowOp.new(ROW, args)
  end
end