Class: Dynamoid::Criteria::Chain

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/dynamoid/criteria/chain.rb

Overview

The criteria chain is equivalent to an ActiveRecord relation (and realistically I should change the name from chain to relation). It is a chainable object that builds up a query and eventually executes it either on an index or by a full table scan.

Instance Attribute Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (Chain) initialize(source)

Create a new criteria chain.

Parameters:

  • source (Class) —

    the class upon which the ultimate query will be performed.



15
16
17
18
19
20
 
# File 'lib/dynamoid/criteria/chain.rb', line 15

def initialize(source)
  @query = {}
  @source = source
  @consistent_read = false
  @scan_index_forward = true
end

Instance Attribute Details

- (Object) consistent_read

Returns the value of attribute consistent_read



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def consistent_read
  @consistent_read
end

- (Object) index=(value)

Sets the attribute index

Parameters:

  • value —

    the value to set the attribute index to.



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def index=(value)
  @index = value
end

- (Object) limit(limit)

Returns the value of attribute limit



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def limit
  @limit
end

- (Object) query

Returns the value of attribute query



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def query
  @query
end

- (Object) source

Returns the value of attribute source



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def source
  @source
end

- (Object) start(start)

Returns the value of attribute start



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def start
  @start
end

- (Object) values

Returns the value of attribute values



9
10
11
 
# File 'lib/dynamoid/criteria/chain.rb', line 9

def values
  @values
end

Instance Method Details

- (Object) all(opts = {})

Returns all the records matching the criteria.

Since:

  • 0.2.0



46
47
48
49
 
# File 'lib/dynamoid/criteria/chain.rb', line 46

def all(opts = {})
  batch opts[:batch_size] if opts.has_key? :batch_size
  records
end

- (Object) batch(batch_size) 



120
121
122
123
124
 
# File 'lib/dynamoid/criteria/chain.rb', line 120

def batch(batch_size)
  raise 'Cannot batch calls when using partitioning' if Dynamoid::Config.partitioning?
  @batch_size = batch_size
  self
end

- (Object) consistent 



38
39
40
41
 
# File 'lib/dynamoid/criteria/chain.rb', line 38

def consistent
  @consistent_read = true
  self
end

- (Object) consistent_opts 



143
144
145
 
# File 'lib/dynamoid/criteria/chain.rb', line 143

def consistent_opts
  { :consistent_read => consistent_read }
end

- (Object) destroy_all

Destroys all the records matching the criteria.



53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
 
# File 'lib/dynamoid/criteria/chain.rb', line 53

def destroy_all
  ids = []
  
  if range?
    ranges = []
    Dynamoid::Adapter.query(source.table_name, range_query).collect do |hash| 
      ids << hash[source.hash_key.to_sym]
      ranges << hash[source.range_key.to_sym]
    end
    
    Dynamoid::Adapter.delete(source.table_name, ids,{:range_key => ranges})
  elsif index
    #TODO: test this throughly and find a way to delete all index table records for one source record
    if index.range_key?
      results = Dynamoid::Adapter.query(index.table_name, index_query.merge(consistent_opts))
    else
      results = Dynamoid::Adapter.read(index.table_name, index_query[:hash_value], consistent_opts)
    end
    
    results.collect do |hash| 
      ids << hash[source.hash_key.to_sym]
      index_ranges << hash[source.range_key.to_sym]
    end
  
    unless ids.nil? || ids.empty?
      ids = ids.to_a
  
      if @start
        ids = ids.drop_while { |id| id != @start.hash_key }.drop(1)
        index_ranges = index_ranges.drop_while { |range| range != @start.hash_key }.drop(1) unless index_ranges.nil?
      end
  
      if @limit           
        ids = ids.take(@limit) 
        index_ranges = index_ranges.take(@limit)
      end
      
      Dynamoid::Adapter.delete(source.table_name, ids)
      
      if index.range_key?
        Dynamoid::Adapter.delete(index.table_name, ids,{:range_key => index_ranges})
      else
        Dynamoid::Adapter.delete(index.table_name, ids)
      end
      
    end
  else
    Dynamoid::Adapter.scan(source.table_name, query, scan_opts).collect do |hash| 
      ids << hash[source.hash_key.to_sym]
    end
    
    Dynamoid::Adapter.delete(source.table_name, ids)
  end   
end

- (Object) each(&block)

Allows you to use the results of a search as an enumerable over the results found.

Since:

  • 0.2.0



139
140
141
 
# File 'lib/dynamoid/criteria/chain.rb', line 139

def each(&block)
  records.each(&block)
end

- (Object) first

Returns the first record matching the criteria.

Since:

  • 0.2.0



111
112
113
 
# File 'lib/dynamoid/criteria/chain.rb', line 111

def first
  limit(1).first
end

- (Object) scan_index_forward(scan_index_forward) 



131
132
133
134
 
# File 'lib/dynamoid/criteria/chain.rb', line 131

def scan_index_forward(scan_index_forward)
  @scan_index_forward = scan_index_forward
  self
end

- (Object) where(args)

The workhorse method of the criteria chain. Each key in the passed in hash will become another criteria that the ultimate query must match. A key can either be a symbol or a string, and should be an attribute name or an attribute name with a range operator.

Examples:

A simple criteria

where(:name => 'Josh')

A more complicated criteria

where(:name => 'Josh', 'created_at.gt' => DateTime.now - 1.day)

Since:

  • 0.2.0



33
34
35
36
 
# File 'lib/dynamoid/criteria/chain.rb', line 33

def where(args)
  args.each {|k, v| query[k.to_sym] = v}
  self
end