|| This report describes a query language front-end developed
for the data server NDB Cluster. NDB Cluster is a high-performance, parallel
data server that is being developed by Ericsson for telecom applications.
The query processor QDB is an extension of the AMOS DBMS with an interface
to NDB Cluster. The query language of AMOS, AMOSQL, supports an Object-Relational
data model and makes it possible to support both a relational model of data
in NDB Cluster, as well as an Object-Oriented (OO) data model. NDB Cluster
supports a flat relational data model and QDB supports transparent translation
of OO queries to flat relations. QDB utilizes the foreign function mechanism
of AMOS which makes it possible to integrate foreign data sources transparently
and with an extensible query optimizer. The report describes the translation
process, query processing and optimization of QDB queries, and details about
the interface between the systems.