The flourishing of mobile devices is driving businesses to deliver data to employees and customers wherever they may be. The potential of mobile gear with mobile data is enormous. A salesperson equipped with a PDA running corporate databases can check order status, sales history, and inventory instantly from the client's site. And drivers can use handheld computers to log deliveries and report order changes for a more efficient supply chain.
Sybase's SQL Anywhere currently dominates the mobile database market. The company has deployed SQL Anywhere to 6 million users at over 10,000 sites and serves 68 percent of the mobile database market, according to a recent Gartner Dataquest study. Other mobile databases include IBM's DB2 Everyplace 7, Microsoft SQL Server 2000 Windows CE Edition, and Oracle9i Lite. Smaller player Gupta Technologies' SQLBase also targets handheld devices.
Mobile databases are often stripped-down versions of their server-based counterparts. They contain only basic SQL operations because of limited resources on the devices. In addition to storage requirements for data tables, the database engines require from 125K to 1MB, depending on how well the vendor was able to streamline its code.
Platform support is a key issue in choosing a mobile database: No organization wants to devote development and training resources to a platform that may become obsolete. Microsoft's mobile database supports Win32 and Windows CE. The IBM, Oracle, and Sybase products support Linux, Palm OS, QNX Neutrino, Symbian EPOC, Windows CE, and Win32.
Mobile databases replicate data among themselves and with a central database. Replication involves examining a database source for changes due to recent transactions and propagating the changes asynchronously to other database targets. Replication must be asynchronous, because users don't have constant connections to the central database.
Transaction-based replication, in which only complete transactions are replicated, is crucial for integrity across the databases: Replicating partial transactions would lead to chaos. Serial transaction replication is important to maintain the same order in each database. This process prevents inconsistencies among the databases. Another consideration in mobile database deployment is how conflicts over multiple updates to the same record will be resolved.
Though the market is still evolving, there's already a sizeable choice of sturdy products that will extend your business's data to mobile workers.
