Module: AWS::Record::FinderMethods

Included in:
Base
Defined in:
lib/aws/record/finder_methods.rb

Instance Method Summary collapse

Instance Method Details

#[](id) ⇒ Record::Base

Returns the record, as a sub-class of Record::Base

Parameters:

  • id (String) —

    The id of the record to load.

Returns:

  • (Record::Base) —

    Returns the record, as a sub-class of Record::Base

Raises:

  • (RecordNotFound) —

    Raises a record not found exception if there was no data found for the given id.



27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/aws/record/finder_methods.rb', line 27

def [] id

  data = sdb_domain.items[id].data.attributes

  raise RecordNotFound, "no data found for id: #{id}" if data.empty?

  obj = self.new
  obj.send(:hydrate, id, data)
  obj

end

#all(options = {}) ⇒ Scope

Returns an enumerable scope object represents all records.

Book.all.each do |book|
  # ...
end

This method is equivalent to find(:all), and therefore you can also pass aditional options. See #find for more information on what options you can pass.

Book.all(:where => { :author' => 'me' }).each do |my_book|
  # ...
end

Returns:

  • (Scope) —

    Returns an enumerable scope object.



102
103
104
 
# File 'lib/aws/record/finder_methods.rb', line 102

def all options = {}
  find(:all, options)
end

#count(options = {}) ⇒ Object Also known as: size

Counts records in SimpleDB.

With no arguments, counts all records:

People.count

Accepts query options to count a subset of records:

People.count(:where => { :boss => true })

You can also count records on a scope object:

People.find(:all).where(:boss => true).count

See #find and Scope#count for more details.

Parameters:

  • options (Hash) (defaults to: {}) —

    ({}) Options for counting records.

Options Hash (options):

  • :where (Mixed) —

    Conditions that determine what records are counted.

  • :limit (Integer) —

    The max number of records to count.



128
129
130
 
# File 'lib/aws/record/finder_methods.rb', line 128

def count(options = {})
  find(:all).count(options)
end

#find(id) ⇒ Object #find(mode, options = {}) ⇒ Object

Finds records in SimpleDB and returns them as objects of the current class.

Finding :all returns an enumerable scope object

People.find(:all, :order => [:age, :desc], :limit => 10).each do |person|
  puts person.name
end

Finding :first returns a single record (or nil)

boss = People.find(:first, :where => { :boss => true })

Find accepts a hash of find modifiers (:where, :order and :limit). You can also choose to omit these modifiers and chain them on the scope object returned. In the following example only one request is made to SimpleDB (when #each is called)

people = People.find(:all)

johns = people.where(:name => 'John Doe')

johns.order(:age, :desc).limit(10).each do |suspects|
  # ...
end

See also #where, #order and #limit for more information and options.

Overloads:

  • #find(id) ⇒ Object

    Parameters:

    • id —

      The record to find, raises an exception if the record is not found.

  • #find(mode, options = {}) ⇒ Object

    Parameters:

    • mode (:all, :first) —

      (:all) When finding :all matching records and array is returned of records. When finding :first then nil or a single record will be returned.

    • options (Hash) (defaults to: {})

    Options Hash (options):

    • :where (Mixed) —

      Conditions that determine what records are returned.

    • :sort (String, Array) —

      The order records should be returned in.

    • :limit (Integer) —

      The max number of records to fetch.



83
84
85
 
# File 'lib/aws/record/finder_methods.rb', line 83

def find *args
  _new_scope.find(*args)
end

#first(options = {}) ⇒ Object?

Returns the first record found for the current class. If there are no records in the current classes domain, then nil is returned.

Returns:

  • (Object, nil) —

    Returns the first record found for the current class. If there are no records in the current classes domain, then nil is returned.



136
137
138
 
# File 'lib/aws/record/finder_methods.rb', line 136

def first options = {}
  _new_scope.find(:first, options)
end

#limit(limit) ⇒ Object

The maximum number of records to return. By default, all records matching the where conditions will be returned from a find.

People.limit(10).each {|person| ... }

Limit can be chained with other scope modifiers:

People.where(:age => 40).limit(10).each {|person| ... }



202
203
204
 
# File 'lib/aws/record/finder_methods.rb', line 202

def limit limit
  _new_scope.limit(limit)
end

#order(attribute, direction = :asc) ⇒ Object

Defines the order in which records are returned when performing a find. SimpleDB only allows sorting by one attribute per request.

# oldest to youngest
People.order(:age, :desc).each {|person| ... }

You can chain order with the other scope modifiers:

Pepole.order(:age, :desc).limit(10).each {|person| ... }

Parameters:

  • attribute (String, Symbol) —

    The attribute in SimpleDB to sort by.

  • direction (:asc, :desc) —

    (:asc) The direction to sort, ascending or descending order.



189
190
191
 
# File 'lib/aws/record/finder_methods.rb', line 189

def order *args
  _new_scope.order(*args)
end

#where(conditions_hash) ⇒ Object #where(sql_fragment[, quote_params, ...]) ⇒ Object

Limits which records are retried from SimpleDB when performing a find.

Simple string condition

Car.where('color = "red" or color = "blue"').each {|car| ... }

String with placeholders for quoting params

Car.where('color = ?', 'red')

Car.where('color = ? OR style = ?', 'red', 'compact')

# produces a condition using in, like: WHERE color IN ('red', 'blue')
Car.where('color = ?', ['red','blue'])

Hash arguments

# WHERE age = '40' AND gender = 'male'
People.where(:age => 40, :gender => 'male').each {|person| ... }

Chaining where with other scope modifiers

# 10 most expensive red cars
Car.where(:color => 'red').order(:price, :desc).limit(10)

Parameters:

  • conditions_hash (Hash) —

    A hash of attributes to values. Each key/value pair from the hash becomes a find condition. All conditions are joined by AND.



171
172
173
 
# File 'lib/aws/record/finder_methods.rb', line 171

def where *args
  _new_scope.where(*args)
end