Extending SGML to accommodate database functions:
		    A Methodological Overview

		Arijit Sengupta		Andrew Dillon

A method for augmenting an SGML document repository with database
functionality is presented. SGML [ISO 8879, 1986] has been widely
accepted as a standard language for writing text with added structural
information that gives the text greater applicability. Recently there
has been a trend to use this structural information as meta-data in
databases. The complex structure of documents, however, makes it
difficult to directly map the structural information in documents to
database structures. In particular, the flat nature of relational
databases makes it extremely difficult to model documents that are
inherently hierarchical in nature. Consequently, documents are modeled
in objectoriented databases [Abiteboul et al., 1993], and
object-relational databases [Holst, 1995], in which SGML documents
are mapped into the corresponding database models and are later
reconstructed as necessary. However, this mapping strategy is not
natural and can potentially cause loss of information in the original
SGML documents. Moreover, interfaces for building queries for current
document databases are mostly built on form-based query techniques and
do not use the "look and feel" of the documents. This paper
introduces an implementation method for a complex-object modeling
technique specifically for SGML documents and describes interface
techniques tailored for text databases. Some of the concepts for a
Structured Document Database Management System (SDDBMS) specifically
designed for SGML documents are described. A small survey of some
current products is also presented to demonstrate the need for such a
system.