Relational DBMSes Trail Objects in XML race, by Polly Strenger
from LANTIMES 7/20/98
If object databases were Cinderella, then extensible Markup Language could legitimately be called their fairy godmother. After years of not quite reaching the mainstream, the object database is finding itself the belle of the ball as relational databases fall short of XML's need for a repository that can Support complex objects.
The recent love affair with XML, for creating data-driven Web-based applications could be hugely lucrative for object database vendors because XML, needs those databases to realize its full potential.
"Storing XML,in an object database is a natural thing to do," said Michael Kay, a systems integrator at ICT. Electronic Business Systems in Bracknell, England. "Both are designed to handle complex data and to bridge the gap between the unstructured free-text document world and to the rigid tabular world of relational databases."
From a business perspective, Web-based applications for E-commerce could be faster and easier to build with both XML and ODBMSes
Less than six months after the W3C (World Wide Web Consortium) approved the specification for XML 1.0 in February, object database vendors arc rushing to the XML community with open arms. Object Design Inc., one such vendor in Burlington, Mass., is
hosting all "XML resource site" on its corporate Web site, while others are reaching out with new product offerings.
But database heavy hitters such as Oracle, IBM, and Informix Corp. have embraced hybrid
object-relational technology instead of pure object databases, even though analysts say that hybrid technologies are more headache than help for developers.
"They've indicated that they're going to be doing things, but it is less concrete," said Michael
Goulde, vice president of research at Patricia Seybold Group Inc. in Boston. "They have some real problems they have to address. The true object vendors are going to be out much more quickly." At this point(, Goulde said, leading database vendors have only made
vague promises to support XML without announcing what product will be available and when.
With several new products announced last month, object database vendors have easily beaten industry leaders to the punch. POET Software Corp.'s Content Management Suite was the first release and was announced at Web Design and Development, a recent trade conference in San Francisco.
The product uses POET's Object Server 5.0 database as an object repository and facilitates the transportation of XML, objects among various clients and applications.
Because of XML's immaturity, there's some confusion over how databases should support the markup language.
"These are still early days for XML," said Steve Withall, a systems architect for Access Systems Research Limited, a systems integrator in Sydney, Australia. "It's not clear what XML support in an ODBMS actually means."
One thing is clear Sophisticated object databases haven't reached their full potential because until XML, there hasn't been a need.
"Up to now, ODBMSes have been limited to storing quite primitive objects-basic data types, images, and so on-because there has been no agreed-upon standard for complex, structured data," Withall said. "XML is such a standard, and it allows ODBMS vendors to
provides users with the means to store, access, and manipulate much richer information."
But don't expect complacency from relational database vendors,
said Tim Bray, co-editor of the XML standard and independent consultant in Vancouver, Canada. "Storing XML in relational databases isn't impossible-just difficult," Bray said. "Nobody knows right now how much work the relational vendors have to do to be able to deal with XML, effectively, but I bet they're working on it. The object-oriented vendors shouldn't be too smug."
The philosophy behind object-oriented programming is that objects not only contain data,
but also metadata, intelligence about what kinds of objects they are. XML operates in the same fashion, letting applications transfer objects that contain both data and information about the schema, or format, that data should be presented ill.
Some developers think that XML has been mislabeled as a kind of "super HTML," when in
fact its capabilities are far more extensive. Although it is a tag-based language like HTML, XML got its "extensible" moniker because developers can define an endless number of new tags.
A DTD (Document Type Definition) in an XML document defines how each tag should be interpreted. As the pace of XML adoption increases, some industry-specific DTDs are emerging. But the beauty of XML is that it is completely platform-, industry-, and application-independent, developers say.
And its simple tag-based structure has made the new markup language a darling among IS
teams that are migrating database information to the Web.
"XML is a language for encoding structured information," said ICL's Kay. "The features that make it good at this are that it is easy for humans to read and write, and easy for software to generate and parse". Previous attempts to create a simple language for transferring data failed, Kay said, because complex software was needed to encode and decode the objects.
Those same faults have plagued object databases. But now that a simple language for encoding and transferring the data objects exists,ODBMSes are ready and waiting to provide a repository for storing those objects.
"XML data is structured and yet it has complex links that are not easily represented by simple rows and tables," said Goulde. "An object database just lends itself much more cleanly to storing XML data than a relational database." Goulde said that using a relational database to store XML objects can take more time and money. "It's an awful lot of overhead compared to what an object database can do."
Theoretically the two technologies are ideally matched, but at this early stage in XML's development some users are questioning how much object databases can actually deliver. "They're a natural fit, if object databases can live up to the demand of typical XML applications Web site content management and serving, document repositories, E-commerce, and metadata storage," said Steven Noels, a senior consultant at s.a.
OFFIS n.v., an IT consulting Company in Zaventum, Belgium. Noels is helping to build a document repository for the Belgium parliament that will provide the government with access to a number of information sources such as Belga, the country's major news wire. XML is used to format query, results between the database and clients. "Object-oriented databases are still regarded as being not very
scalable or robust," he said.
"Object-oriented support for XML is still mostly just a good idea," said Bray. "There are several repositories dating back to the SGML days, but the idea that object-oriented database vendors will support this directly is fairly recent."
Easier E-commerce
But if ODBMSes can rise to the challenge, the benefit to businesses migrating data to the Web could be immeasurable, said Carl Olofson, research director at International Data Corp. in Framingham, Mass. "The end result is that you don't have to have a degree in
computer science to put an information center together," Olofson said.
If object database vendors can build effective XML management capabilities into their- database, Web data publication can be faster, more robust, and easier for IS teams. The complexity of transporting huge amounts of data to the Web has been difficult without a standard format. "Once you get beyond a certain level of complexity, it's just not possible using a mish-mash of ordinary tools and files to construct and keep coherent a very complicated collection of information," Olofson said.
There is little doubt about XML's value as a language for encoding and transferring data.
"Somebody quotes XML as being the ASCII format of the future, and I think that that person is right in his statement," said OFFIS' Noels. "It will play a major role in serving the content
of databases to the Internet. It's only a matter of time."
Object databases may be well-suited to Support XML's rise to the top, but with such lucrative prospects relational databases can't be far behind.
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