TNS, Transport Network Substrate, is a foundation technology, built into the Oracle Net foundation layer that works with any standard network transport protocol.
ODBC, Open Database Communication, a standard API (application program interface) developed by Microsoft for Windows applications to communicate with database management systems.
Oracle offers ODBC drivers to allow Windows applications to connect Oracle server through ODBC.
Based on Oracle Web site: Oracle Database 10g Express Edition (Oracle Database XE) is an entry-level, small-footprint database based on the Oracle Database 10g Release 2 code base that's free to develop, deploy, and distribute; fast to download; and simple to administer. Oracle Database XE is a great starter database for:
* Developers working on PHP, Java, .NET, and Open Source applications
* DBAs who need a free, starter database for training and deployment
* Independent Software Vendors (ISVs) and hardware vendors who want a starter database to distribute free of charge
* Educational institutions and students who need a free database for their curriculum
Oracle Database XE is free for runtime usage with the following limitations:
* Supports up to 4GB of user data (in addition to Oracle system data)
* Single instance only of Oracle Database XE on any server
* May be installed on a multiple CPU server, but only executes on one processor in any server
* May be installed on a server with any amount of memory, but will only use up to 1GB RAM of available memory
Oracle Database 10g Express Edition is available for two types of operating Systems:
* Linux x86 - Debian, Mandriva, Novell, Red Hat and Ubuntu
* Microsoft Windows