Class Rddb::View
In: lib/rddb/view.rb
Parent: Object

A view on the database. Views are used to express queries. Views use Ruby blocks to process the documents in the document store and produce responses. Views can be materialized to improve performance.

Methods

database   distributed?   do_query   materialization_store   materialize   materialize_if   materialized?   new   reduce_with   require_materialization   should_refresh?  

Attributes

name  [R]  Get the name of the view.

Public Class methods

new(database, name, options={}, &block)

Initialize the view instance with the given name and the block used to map the documents to the view result set.

Options:

[Source]

    # File lib/rddb/view.rb, line 16
16:     def initialize(database, name, options={}, &block)
17:       @database = database
18:       @name = name
19:       @map_with = block
20:       
21:       @materialization_store = options[:materialization_store] if options[:materialization_store]
22:       @distributed = options[:distributed]
23:     end

Public Instance methods

distributed?()

Return true if the view querying is distributed.

[Source]

    # File lib/rddb/view.rb, line 89
89:     def distributed?
90:       @distributed
91:     end
materialize(document_store)

Materialize the view

[Source]

    # File lib/rddb/view.rb, line 48
48:     def materialize(document_store)
49:       #puts "querying for materialization"
50:       @materialized = do_query(document_store)
51:       materialization_store.store(self)
52:     end
materialize_if(&block)

Define a block that is used to determine if the view requires updating. This is only used when a view is materialized.

[Source]

    # File lib/rddb/view.rb, line 63
63:     def materialize_if(&block)
64:       @materialize_check = block
65:       return self
66:     end
materialized?()

Return true if the view is a materialized view.

[Source]

    # File lib/rddb/view.rb, line 74
74:     def materialized?
75:       !@materialize_check.nil?
76:     end
reduce_with(&block)

Provide a block that is used to reduce the result set upon completion of the mapping.

[Source]

    # File lib/rddb/view.rb, line 56
56:     def reduce_with(&block)
57:       @reduce_with = block
58:       return self
59:     end
require_materialization()

Indicate that materialization is required before responding to queries.

[Source]

    # File lib/rddb/view.rb, line 69
69:     def require_materialization
70:       @require_materialization = true
71:     end
should_refresh?(document)

Return true if the view requires an update for the specified document.

[Source]

    # File lib/rddb/view.rb, line 79
79:     def should_refresh?(document)
80:       materialized? && @materialize_check.call(document)
81:     end

Protected Instance methods

database()

Get the database instance

[Source]

     # File lib/rddb/view.rb, line 116
116:     def database
117:       @database
118:     end
do_query(document_store, args={})

Interal query

[Source]

     # File lib/rddb/view.rb, line 95
 95:     def do_query(document_store, args={})
 96:       # map
 97:       results = do_map(document_store, args)
 98:       # reduce (if necessary)
 99:       @reduce_with.nil? ? results : @reduce_with.call(results)
100:     end
materialization_store()

Get the materialization store instance, defaulting to a RamMaterializationStore.

[Source]

     # File lib/rddb/view.rb, line 121
121:     def materialization_store
122:       @materialization_store ||= MaterializationStore::RamMaterializationStore.new
123:     end

[Validate]