Implementing Parameterized Range Types in an Extensible DBMS

Abstract

A parameterized type defines a family of related types. For example, a single parameterized type ARRAY provides a common definition for array of INTEGER, array of FLOAT, and array of rows of a certain row type. SQL3 proposes support for user-defined parameterized types (or UDPTs for short), but we have yet to see any full implementation in a commercial DBMS. In this paper, we show how we implemented UDPTs Range and RangeSet using the DataBlade and Fastpath extensibility features of Informix. We also describe the application of these UDPTs in building a temporal database with TSQL2-like features. We found that implementing temporal database primitives using UDPTs required much less development effort and is more flexible than our earlier approach that used regular, non-parameterized user-defined types. We report some lessons learned in the implementation process, and propose a ``wish list'' of DBMS extensibility features required for full support of UDPTs. Although our implementation is based on Informix, we expect our experience and findings to be relevant to anyone implementing UDPTs in an extensible DBMS.