The self-contained application and database were necessary because Kaiser Permanente's IS operation has no experience with distribution systems and can't provide any support, says Jonathan Rothschild, manager of startup services. "There are no IS people here at all," he says from the HMO's warehouse in Chino, Calif.

Compatibility and connectivity with other enterprise systems, support for multiple data types, and scalability are the chief weaknesses of the current crop of embedded database tools, according to a survey of more than 400 embedded systems developers conducted earlier this year by Evans Data Corp. But those developers say they were relatively pleased with the products' integration capabilities, portability, and support for real-time operating systems.

Embeddable databases are often closely tied to a set of development tools for building applications around the database. And those tools are frequently what lead a company to buy one embedded database over another, Gartner Dataquest analyst Colleen Graham says. Progress, for example, sells its database as part of its OpenEdge application development and deployment platform, which also includes development tools and an application server. InterSystems provides its Cache Studio application development environment.

HAB Inc. markets a set of management applications for public-housing authorities based on Gupta's SQLBase and developed using that vendor's tools. "Getting both from under one roof was a big deal for us," says Tom Fahey, HAB's development manager. "If you get the database from one place and the development tools from another, there could be technology issues."

Some vendors that sell development tools and database software have used proprietary programming interfaces. Developers today are demanding that embeddable databases provide more standard interfaces such as Open Database Connectivity, Java Database Connectivity, OLE DB, and Active Data Objects.

In Pervasive 8.0, those standard interfaces are supported along with the vendor's proprietary Btrieve application programming interface. In its RDM Server 4.0 database released in July, Birdstep Technology ASA supports ODBC, JDBC, and Dynamic Database Definition Language for modifying a database's structure.

By the end of the year, Gupta plans to offer a native .Net data provider that will let SQLBase exchange data with .Net applications. And InterSystems' Cache database offers an ODBC interface that Molecular Pathology Laboratory Network plans to use to link its laboratory software with IT systems at other medical laboratories, CIO Billings says.

Customers are also starting to ask for data-replication capabilities to let databases built into mobile devices or products such as vending machines sync up with a database back at headquarters. Borland already provides such capabilities in its InterBase embeddable database, while other vendors, such as Progress, plan to add such features soon. A train manufacturer uses the replication capabilities in FairCom's database to download collected diagnostics data from locomotive engines to a central system for analysis, for example.

Suppliers of native XML databases such as Excelon, Ipedo, and Software AG say they're seeing increasing demand for their products for embedded applications. XML databases are designed to store and manage XML documents and other content.

One Ipedo customer embeds the vendor's XML database in an application used to manage digital assets such as training videos. Ipedo says embedded applications account for about one-third of its sales.

Last month, Birdstep debuted RDM XML, an embeddable XML database for mobile applications. Adding XML support to databases is on the research and development to-do lists of other vendors as well.

Vendors of open-source databases such as MySQL, NuSphere, and Sleepycat Software also have been making a run at the embedded database market. Open-source database vendors sell products and services based on the free MySQL and PostgreSQL database technologies.

But competitors say that open-source databases don't have the scalability and reliability of established, proprietary products. "Transactional integrity is the bread-and-butter of embedded databases," says Jacob Christfort, product development VP and chief technology officer of Oracle's mobile products and services division, which develops the Oracle9i Lite software.

Industry analysts say open-source databases may be a threat to established vendors such as Progress and InterSystems, but not in the immediate future. Says Aberdeen Group's Kernochan, "I don't see them having a presence in the market for the next two years."