Module | Sequel::Plugins::DatasetAssociations::DatasetMethods |
In: |
lib/sequel/plugins/dataset_associations.rb
|
For the association given by name, return a dataset of associated objects such that it would return the union of calling the association method on all objects returned by the current dataset.
This supports most options that are supported when eager loading. However, it will only work for limited associations or *_one associations with orders if the database supports window functions.
# File lib/sequel/plugins/dataset_associations.rb, line 80 80: def associated(name) 81: raise Error, "unrecognized association name: #{name.inspect}" unless r = model.association_reflection(name) 82: ds = r.associated_class.dataset 83: sds = opts[:limit] ? self : unordered 84: ds = case r[:type] 85: when :many_to_one 86: ds.filter(r.qualified_primary_key=>sds.select(*Array(r[:qualified_key]))) 87: when :one_to_one, :one_to_many 88: r.send(:apply_filter_by_associations_limit_strategy, ds.filter(r.qualified_key=>sds.select(*Array(r.qualified_primary_key)))) 89: when :many_to_many, :one_through_one 90: mds = r.associated_class.dataset. 91: join(r[:join_table], r[:right_keys].zip(r.right_primary_keys)). 92: select(*Array(r.qualified_right_key)). 93: where(r.qualify(r.join_table_alias, r[:left_keys])=>sds.select(*r.qualify(model.table_name, r[:left_primary_key_columns]))) 94: ds.filter(r.qualified_right_primary_key=>r.send(:apply_filter_by_associations_limit_strategy, mds)) 95: when :many_through_many, :one_through_many 96: fre = r.reverse_edges.first 97: fe, *edges = r.edges 98: edges << r.final_edge 99: mds = model. 100: select(*Array(r.qualify(fre[:table], fre[:left]))). 101: join(fe[:table], Array(fe[:right]).zip(Array(fe[:left])), :implicit_qualifier=>model.table_name). 102: where(r.qualify(fe[:table], fe[:right])=>sds.select(*r.qualify(model.table_name, r[:left_primary_key_columns]))) 103: edges.each{|e| mds = mds.join(e[:table], Array(e[:right]).zip(Array(e[:left])))} 104: ds.filter(r.qualified_right_primary_key=>r.send(:apply_filter_by_associations_limit_strategy, mds)) 105: when :pg_array_to_many 106: ds.filter(Sequel[r.primary_key=>sds.select{Sequel.pg_array_op(r.qualify(r[:model].table_name, r[:key])).unnest}]) 107: when :many_to_pg_array 108: ds.filter(Sequel.function(:coalesce, Sequel.pg_array_op(r[:key]).overlaps(sds.select{array_agg(r.qualify(r[:model].table_name, r.primary_key))}), false)) 109: else 110: raise Error, "unrecognized association type for association #{name.inspect}: #{r[:type].inspect}" 111: end 112: 113: ds = r.apply_eager_dataset_changes(ds).unlimited 114: 115: if r[:dataset_associations_join] 116: case r[:type] 117: when :many_to_many, :one_through_one 118: ds = ds.join(r[:join_table], r[:right_keys].zip(r.right_primary_keys)) 119: when :many_through_many, :one_through_many 120: (r.reverse_edges + [r.final_reverse_edge]).each{|e| ds = ds.join(e[:table], e.fetch(:only_conditions, (Array(e[:left]).zip(Array(e[:right])) + Array(e[:conditions]))), :table_alias=>ds.unused_table_alias(e[:table]), :qualify=>:deep, &e[:block])} 121: end 122: end 123: 124: ds 125: end