Class: Sequel::Postgres::PGArray

Inherits:
Array show all
Defined in:
lib/sequel/extensions/pg_array.rb,
lib/sequel/extensions/pg_array_ops.rb

Overview

Represents a PostgreSQL array column value.

Defined Under Namespace

Modules: DatabaseMethods Classes: Creator, JSONCreator, Parser

Constant Summary collapse

ARRAY = 
"ARRAY".freeze
DOUBLE_COLON = 
'::'.freeze
EMPTY_BRACKET = 
'[]'.freeze
OPEN_BRACKET = 
'['.freeze
CLOSE_BRACKET = 
']'.freeze
COMMA = 
','.freeze
BACKSLASH = 
'\\'.freeze
EMPTY_STRING = 
''.freeze
OPEN_BRACE = 
'{'.freeze
CLOSE_BRACE = 
'}'.freeze
NULL = 
'NULL'.freeze
QUOTE = 
'"'.freeze
ARRAY_TYPES =

Hash of database array type name strings to symbols (e.g. ‘double precision’ => :float), used by the schema parsing.

{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Array

#case, #pg_array, #pg_json, #sql_expr, #sql_negate, #sql_or, #sql_string_join, #sql_value_list, #~

Constructor Details

#initialize(array, type = nil) ⇒ PGArray

Set the array to delegate to, and a database type.



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# File 'lib/sequel/extensions/pg_array.rb', line 439

def initialize(array, type=nil)
  super(array)
  @array_type = type
end

Instance Attribute Details

#array_type ⇒ Object

The type of this array. May be nil if no type was given. If a type is provided, the array is automatically casted to this type when literalizing. This type is the underlying type, not the array type itself, so for an int4[] database type, it should be :int4 or ‘int4’



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# File 'lib/sequel/extensions/pg_array.rb', line 436

def array_type
  @array_type
end

Class Method Details

.register(db_type, opts = {}, &block) ⇒ Object

Registers an array type that the extension should handle. Makes a Database instance that has been extended with DatabaseMethods recognize the array type given and set up the appropriate typecasting. Also sets up automatic typecasting for the native postgres adapter, so that on retrieval, the values are automatically converted to PGArray instances. The db_type argument should be the exact database type used (as returned by the PostgreSQL format_type database function). Accepts the following options:

:array_type

The type to automatically cast the array to when literalizing the array. Usually the same as db_type.

:converter

A callable object (e.g. Proc), that is called with each element of the array (usually a string), and should return the appropriate typecasted object.

:oid

The PostgreSQL OID for the array type. This is used by the Sequel postgres adapter to set up automatic type conversion on retrieval from the database.

:parser

Can be set to :json to use the faster JSON-based parser. Note that the JSON-based parser can only correctly handle integers values correctly. It doesn’t handle full precision for numeric types, and doesn’t handle NaN/Infinity values for floating point types.

:scalar_oid

Should be the PostgreSQL OID for the scalar version of this array type. If given, automatically sets the :converter option by looking for scalar conversion proc.

:scalar_typecast

Should be a symbol indicating the typecast method that should be called on each element of the array, when a plain array is passed into a database typecast method. For example, for an array of integers, this could be set to :integer, so that the typecast_value_integer method is called on all of the array elements. Defaults to :type_symbol option.

:type_symbol

The base of the schema type symbol for this type. For example, if you provide :integer, Sequel will recognize this type as :integer_array during schema parsing. Defaults to the db_type argument.

:typecast_method

If given, specifies the :type_symbol option, but additionally causes no typecasting method to be created in the database. This should only be used to alias existing array types. For example, if there is an array type that can be treated just like an integer array, you can do :typecast_method=>:integer.

If a block is given, it is treated as the :converter option.



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# File 'lib/sequel/extensions/pg_array.rb', line 147

def self.register(db_type, opts={}, &block)
  db_type = db_type.to_s
  typecast_method = opts[:typecast_method]
  type = (typecast_method || opts[:type_symbol] || db_type).to_sym

  if converter = opts[:converter]
    raise Error, "can't provide both a block and :converter option to register" if block
  else
    converter = block
  end

  if soid = opts[:scalar_oid]
    raise Error, "can't provide both a converter and :scalar_oid option to register" if converter 
    raise Error, "no conversion proc for :scalar_oid=>#{soid.inspect} in PG_TYPES" unless converter = PG_TYPES[soid]
  end

  array_type = (opts[:array_type] || db_type).to_s.dup.freeze
  creator = (opts[:parser] == :json ? JSONCreator : Creator).new(array_type, converter)

  ARRAY_TYPES[db_type] = :"#{type}_array"

  DatabaseMethods.define_array_typecast_method(type, creator, opts.fetch(:scalar_typecast, type)) unless typecast_method

  if oid = opts[:oid]
    Sequel::Postgres::PG_TYPES[oid] = creator
  end

  nil
end

Instance Method Details

#op ⇒ Object

Wrap the PGArray instance in an ArrayOp, allowing you to easily use the PostgreSQL array functions and operators with literal arrays.



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# File 'lib/sequel/extensions/pg_array_ops.rb', line 207

def op
  ArrayOp.new(self)
end

#sql_literal_append(ds, sql) ⇒ Object

Append the array SQL to the given sql string. If the receiver has a type, add a cast to the database array type.



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# File 'lib/sequel/extensions/pg_array.rb', line 447

def sql_literal_append(ds, sql)
  sql << ARRAY
  _literal_append(sql, ds, to_a)
  if at = array_type
    sql << DOUBLE_COLON << at.to_s << EMPTY_BRACKET
  end
end