JDO Query Language (JDOQL)

The JDO Query Language interface (JDOQL) has the following goals:

  • Query language neutrality. The underlying query language might be a relational query language such as SQL; an object database query language such as OQL; or a specialized API to a hierarchical database or mainframe EIS system.
  • Optimization to specific query language. The Query interface is capable of optimizations; therefore, the interface has enough user-specified information to allow for the JDO implementation to exploit data source specific query features.
  • Accommodation of multi-tier architectures. Queries may be executed entirely in memory, or may be delegated to a back end query engine. The JDO Query interface provides for both types of query execution strategies.
  • Large result set support. Queries might return massive numbers of JDO instances that match the query. The JDO Query architecture provides for processing the results within the resource constraints of the execution environment.
  • Compiled query support. Parsing queries may be resource-intensive, and in many applications can be done during application development or deployment, prior to execution time. The query interface allows for compiling queries and binding run-time parameters to the bound queries for execution.
Additional information on JDOQL, including a BNF grammar, can be found at the Sun website.

Context for JDO Query Language (JDOQL)

Related Articles for JDO Query Language (JDOQL)

The Savvy Manager's Guide

is also the author of a book that explains Web Services, service-oriented architecture, and Cloud Computing in an easy-to-understand, non-technical manner.

Web Services, Service-Oriented Architectures, and Cloud Computing: The Savvy Manager's Guide

by with David Dick

This is a guide for the savvy manager who wants to capitalize on the wave of change that is occurring with Web Services, service-oriented architecture, and—more recently—Cloud Computing. The changes wrought by these technologies will require both a basic grasp of the technologies and an effective way to deal with how these changes will affect the people who build and use the systems in our organizations. This book covers both issues. Managers at all levels of all organizations must be aware of both the changes that we are now seeing and ways to deal with issues created by those changes.