Historically, managing Oracle software could be a painful task. This was because the DBA was largely responsible for ensuring that incompatible products were kept separate. It was not uncommon to install one product, a second, and a third satisfactorily—then installation of a fourth would break the other three. The problem of incompatibilities lies in the use of the base libraries. The base libraries Identify the Tools for Administering an Oracle Database 87
provide facilities that are common to all Oracle products. For example, all Oracle products use the Oracle Net communications protocol; it is impossible to install a product without it. If two products are built on the same version of the base libraries, then (theoretically) they can coexist in the same Oracle Home. An Oracle Home is the location of an Oracle product installation: a set of files in a directory structure. Before the Oracle Universal Installer, each product had its own self-contained installation routine, which was sometimes not too clever at identifying incompatibilities with already installed products.
The OUI is written in Java, using JDK/JRE1.5. This means that it is the same on all platforms, with the exception of certain well-know and trivial variations in the Java user interface, such as whether windows have square or rounded corners. The OUI can be installed as a self-contained product in its own Oracle Home, but this is not usually necessary, as it is shipped with every other Oracle product and can be launched from the product installation CD (or DVD); it will install itself into the Oracle Home along with the product. There are different versions of the OUI, and if a product comes with an earlier version than one already installed on the machine, then it will usually be a good idea (and may indeed be necessary) to install the product using the already-installed version, from the existing Oracle Home. When the OUI prompts for the location of a products.xml file, specify the DVD with the product you want to install.
You know, I was thinking about that old cartoon He Man and the Masters of the Universe. And, I got to thinking, that's a pretty lame universe. I mean, one planet, populated by maybe a dozen people, and no one can seem to get a decent pair of pants.
You know what's an even worse universe? Java.
Thanks, Oracle, for an installer that is a sweet PITA to run over SSH.