Reference is not only one of the important modeling mechanism

but also beneficial to the design and implementations of join algorithms.Based on the features of ORDM(Object-Relational Data Model) and the query language

a new reference based join algorithm Sort-Loops is represented.Sort-Loops attempts to read most of the outer table as possible in one pass

and then sorts the tuples according to their reference's PID.By the sorting techniques

there is no duplicate read of the same page in a pass

and the performance is further improved by reading the inner table in order of its physical address.Sort-Loops is a useful and high performance join algorithm.It is further validated by the analysis and comparison with other algorithms.