Enterprise J2ME Developing Mobile Java Applications [Electronic resources] نسخه متنی

Chapter 14. Access Backend Databases

CHAPTER OVERVIEW

Why Remote Database?

Remote Database Access Schemes

The Oracle J2ME SQL SDK

Legacy Applications

Using Simplicity for Legacy Databases

In Chapter 13, we discussed how mobile applications keep themselves updated via synchronization with backend databases. However, synchronization is not efficient when we deal with frequent (real-time) updates. For many applications, we also need ways to access the remote back end directly. Direct access and synchronization functionalities can coexist in the same application and complement each other. On the CDC or PersonalJava platforms, we can rely on the standard JDBC APIs. But on the CLDC/MIDP platforms, the only option is HTTP proxy servers. In this chapter, we use the Oracle J2ME SDK to demonstrate how to expose simple SQL services via an HTTP gateway.

To migrate existing enterprise applications to the mobile commerce, we need to build mobile clients that can access not only relational databases but legacy databases as well. This chapter explains how to build mobile clients for legacy systems using screen scraping tools provided with the Simplicity IDE tools.