module CompositePrimaryKeys::Predicates
Public Instance Methods
cpk_and_predicate(predicates)
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# File lib/composite_primary_keys/composite_predicates.rb, line 7 def cpk_and_predicate(predicates) if predicates.length == 1 predicates.first else Arel::Nodes::And.new(predicates) end end
cpk_id_predicate(table, keys, values)
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# File lib/composite_primary_keys/composite_predicates.rb, line 34 def cpk_id_predicate(table, keys, values) # We zip on values then keys in case values are not provided for each key field eq_predicates = values.zip(keys).map do |value, key| table[key].eq(value) end cpk_and_predicate(eq_predicates) end
cpk_in_predicate(table, primary_keys, ids)
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# File lib/composite_primary_keys/composite_predicates.rb, line 53 def cpk_in_predicate(table, primary_keys, ids) if primary_keys.length == 2 cpk_in_predicate_with_grouped_keys(table, primary_keys, ids) else cpk_in_predicate_with_non_grouped_keys(table, primary_keys, ids) end end
cpk_in_predicate_with_grouped_keys(table, primary_keys, ids)
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# File lib/composite_primary_keys/composite_predicates.rb, line 69 def cpk_in_predicate_with_grouped_keys(table, primary_keys, ids) keys_by_first_column_name = Hash.new { |hash, key| hash[key] = [] } keys_by_second_column_name = Hash.new { |hash, key| hash[key] = [] } ids.map.each do |first_key_part, second_key_part| keys_by_first_column_name[first_key_part] << second_key_part keys_by_second_column_name[second_key_part] << first_key_part end low_cardinality_column_name, high_cardinality_column_name, groups = \ if keys_by_first_column_name.size <= keys_by_second_column_name.size [primary_keys.first, primary_keys.second, keys_by_first_column_name] else [primary_keys.second, primary_keys.first, keys_by_second_column_name] end and_predicates = groups.map do |low_cardinality_value, high_cardinality_values| non_nil_high_cardinality_values = high_cardinality_values.compact in_clause = table[high_cardinality_column_name].in(non_nil_high_cardinality_values) inclusion_clauses = if non_nil_high_cardinality_values.size != high_cardinality_values.size Arel::Nodes::Grouping.new( Arel::Nodes::Or.new( in_clause, table[high_cardinality_column_name].eq(nil) ) ) else in_clause end Arel::Nodes::And.new( [ table[low_cardinality_column_name].eq(low_cardinality_value), inclusion_clauses ] ) end cpk_or_predicate(and_predicates) end
cpk_in_predicate_with_non_grouped_keys(table, primary_keys, ids)
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# File lib/composite_primary_keys/composite_predicates.rb, line 61 def cpk_in_predicate_with_non_grouped_keys(table, primary_keys, ids) and_predicates = ids.map do |id| cpk_id_predicate(table, primary_keys, id) end cpk_or_predicate(and_predicates) end
cpk_join_predicate(table1, key1, table2, key2)
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# File lib/composite_primary_keys/composite_predicates.rb, line 42 def cpk_join_predicate(table1, key1, table2, key2) key1_fields = Array(key1).map {|key| table1[key]} key2_fields = Array(key2).map {|key| table2[key]} eq_predicates = key1_fields.zip(key2_fields).map do |key_field1, key_field2| key_field2 = Arel::Nodes::Quoted.new(key_field2) unless Arel::Attributes::Attribute === key_field2 key_field1.eq(key_field2) end cpk_and_predicate(eq_predicates) end
cpk_or_predicate(predicates, group = true)
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# File lib/composite_primary_keys/composite_predicates.rb, line 15 def cpk_or_predicate(predicates, group = true) if predicates.length <= 1 predicates.first else split_point = predicates.length / 2 predicates_first_half = predicates[0...split_point] predicates_second_half = predicates[split_point..-1] or_predicate = ::Arel::Nodes::Or.new(cpk_or_predicate(predicates_first_half, false), cpk_or_predicate(predicates_second_half, false)) if group ::Arel::Nodes::Grouping.new(or_predicate) else or_predicate end end end