Class: ROM::Memory::Dataset
- Inherits:
-
Object
- Object
- ROM::Memory::Dataset
- Includes:
- ArrayDataset
- Defined in:
- lib/rom/memory/dataset.rb
Overview
In-memory dataset
This class can be used as a base class for other adapters.
Instance Method Summary collapse
-
#delete(tuple) ⇒ Dataset
Delete tuples from a dataset.
-
#insert(tuple) ⇒ Dataset
(also: #<<)
Insert tuple into a dataset.
-
#join(*args) ⇒ Dataset
Join with other datasets.
-
#order(*fields) ⇒ Dataset
Sort a dataset.
-
#project(*names) ⇒ Dataset
Project a dataset.
-
#restrict(criteria = nil) ⇒ Dataset
Restrict a dataset.
Methods included from ArrayDataset
Methods included from DataProxy::ClassMethods
Methods included from EnumerableDataset
Instance Method Details
#delete(tuple) ⇒ Dataset
Delete tuples from a dataset
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# File 'lib/rom/memory/dataset.rb', line 108 def delete(tuple) data.delete(tuple) self end |
#insert(tuple) ⇒ Dataset Also known as: <<
Insert tuple into a dataset
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# File 'lib/rom/memory/dataset.rb', line 95 def insert(tuple) data << tuple self end |
#join(*args) ⇒ Dataset
Join with other datasets
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# File 'lib/rom/memory/dataset.rb', line 20 def join(*args) left, right = args.size > 1 ? args : [self, args.first] join_map = left.each_with_object({}) { |tuple, h| others = right.to_a.find_all { |t| (tuple.to_a & t.to_a).any? } (h[tuple] ||= []).concat(others) } tuples = left.flat_map { |tuple| join_map[tuple].map { |other| tuple.merge(other) } } self.class.new(tuples, ) end |
#order(*fields) ⇒ Dataset
Sort a dataset
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# File 'lib/rom/memory/dataset.rb', line 78 def order(*fields) nils_first = fields.pop[:nils_first] if fields.last.is_a?(Hash) sort do |a, b| fields # finds the first difference between selected fields of tuples .map { |n| __compare__ a[n], b[n], nils_first } .detect(-> { 0 }) { |r| r != 0 } end end |
#project(*names) ⇒ Dataset
Project a dataset
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# File 'lib/rom/memory/dataset.rb', line 63 def project(*names) map { |tuple| tuple.reject { |key| !names.include?(key) } } end |
#restrict(criteria = nil) ⇒ Dataset
Restrict a dataset
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# File 'lib/rom/memory/dataset.rb', line 42 def restrict(criteria = nil) return find_all { |tuple| yield(tuple) } unless criteria find_all do |tuple| criteria.all? do |k, v| case v when Array then v.include?(tuple[k]) when Regexp then tuple[k].match(v) else tuple[k].eql?(v) end end end end |