Input: relationship table Output: attribute index table Map (LongWritable, DataText, DataText, DataText) Input: key:=entity ID, value:=tuple FOR each (key, value) DO FOR each property DO output_key := property ID + “*” + property value output_value := entity ID Reduce (DataText, DataText, NullWritable, DataText) FOR each value in value_table entity ID:= property ID + “*” + entity ID output_key:= null output_value:= all of entity ID in value_table |