Class Sequel::Postgres::PGRowOp
In: lib/sequel/extensions/pg_row_ops.rb
Parent: SQL::PlaceholderLiteralString

This class represents a composite type expression reference.

Methods

*   []   splat   wrap  

Classes and Modules

Module Sequel::Postgres::PGRowOp::ExpressionMethods

Constants

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

Public Class methods

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

[Source]

     # File lib/sequel/extensions/pg_row_ops.rb, line 99
 99:       def self.wrap(expr)
100:         PGRowOp.new(WRAP, [expr])
101:       end

Public Instance methods

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).*

[Source]

     # File lib/sequel/extensions/pg_row_ops.rb, line 124
124:       def *(ce=(arg=false;nil))
125:         if arg == false
126:           Sequel::SQL::ColumnAll.new([self])
127:         else
128:           super(ce)
129:         end
130:       end

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.

[Source]

     # File lib/sequel/extensions/pg_row_ops.rb, line 108
108:       def [](member)
109:         case member
110:         when Symbol, SQL::Identifier
111:           PGRowOp.new(QUALIFY, [self, member])
112:         else
113:           PGRowOp.wrap(Sequel.pg_array_op(self)[member])
114:         end
115:       end

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

[Source]

     # File lib/sequel/extensions/pg_row_ops.rb, line 143
143:       def splat(cast_to=nil)
144:         if args.length > 1
145:           raise Error, 'cannot splat a PGRowOp with multiple arguments'
146:         end
147: 
148:         if cast_to
149:           PGRowOp.new(ROW_CAST, args + [cast_to])
150:         else
151:           PGRowOp.new(ROW, args)
152:         end
153:       end

[Validate]