Free to develop, deploy, and distribute
Oracle Database 11g Express Edition (Oracle Database XE) is an entry-level, small-footprint database based on the Oracle Database 11g Release 2 code base. It's free to develop, deploy, and distribute; fast to download; and simple to administer.
Oracle Database XE is a great starter database for:
With Oracle Database XE, you can now develop and deploy applications with a powerful, proven, industry-leading infrastructure, and then upgrade when necessary without costly and complex migrations.
Oracle Database XE can be installed on any size host machine with any number of CPUs (one database per machine), but XE will store up to 11GB of user data, use up to 1GB of memory, and use one CPU on the host machine.
Support is provided through a free Oracle Discussion Forum monitored by Oracle employees as well as community experts.