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. It doesn‘t support limits on the associations, or one_to_one associations that are really one_to_many and use an order to select the first matching object. In both of those cases, this will return an array of all matching objects.
# File lib/sequel/plugins/dataset_associations.rb, line 73 73: def associated(name) 74: raise Error, "unrecognized association name: #{name.inspect}" unless r = model.association_reflection(name) 75: ds = r.associated_class.dataset 76: sds = opts[:limit] ? self : unordered 77: ds = case r[:type] 78: when :many_to_one 79: ds.filter(r.qualified_primary_key=>sds.select(*Array(r[:qualified_key]))) 80: when :one_to_one, :one_to_many 81: ds.filter(r.qualified_key=>sds.select(*Array(r.qualified_primary_key))) 82: when :many_to_many 83: ds.filter(r.qualified_right_primary_key=>sds.select(*Array(r.qualified_right_key)). 84: join(r[:join_table], r[:left_keys].zip(r[:left_primary_keys]), :implicit_qualifier=>model.table_name)) 85: when :many_through_many 86: fre = r.reverse_edges.first 87: fe, *edges = r.edges 88: sds = sds.select(*Array(r.qualify(fre[:table], fre[:left]))). 89: join(fe[:table], Array(fe[:right]).zip(Array(fe[:left])), :implicit_qualifier=>model.table_name) 90: edges.each{|e| sds = sds.join(e[:table], Array(e[:right]).zip(Array(e[:left])))} 91: ds.filter(r.qualified_right_primary_key=>sds) 92: when :pg_array_to_many 93: ds.filter(Sequel.expr(r.primary_key=>sds.select{Sequel.pg_array_op(r.qualify(r[:model].table_name, r[:key])).unnest})) 94: when :many_to_pg_array 95: 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)) 96: else 97: raise Error, "unrecognized association type for association #{name.inspect}: #{r[:type].inspect}" 98: end 99: ds = model.apply_association_dataset_opts(r, ds) 100: r[:extend].each{|m| ds.extend(m)} 101: ds 102: end