Periodically, Microsoft and Oracle release new versions of their RDBMS software. Oralce 11g, SQL Server 2008 being the latest. The new software releases typically provide new features and better performance.

This alone is not always a strong enough reason to go through the cost of purchasing the new software. There is then the overhead of testing that all of your existing functionality works as expected on this new platform. There are sometimes however good reasons to upgrade to the latest version of the software. This could be for new or better features or because the system will run faster on the later RDBMS platform.

Recently, a good example of this has been the introduction of 64bit SQL Server. This not only allows for faster processing, but probably more importantly, allows for much more efficient use of memory in servers which have more than 2GB of memory.

Another reason, is that you may be forced into upgrading. You may find that the current version of the RDBMS software that AGRESSO is running on, will soon be unsupported by the vendor. You may then be faced with the option of upgrading to the next release, or upgrading two versions of the RDBMS software to the current release.

Similarly, the next version of AGRESSO that you plan on upgrading to, is not supported on the current version of the RDBMS platform that you are using.

Add to this, that in some organisations the strategic decision to switch from Oracle to SQL Server (or vice versa) will be made.

The initial upgrade of either Microsoft SQL Server or Oracle would always be carried out on a test system. Once the system has been tested then the live upgrade can be planned. Given the nature of the upgrade there will always be an element of downtime. This figure can be roughly approximated from the length of time that the test upgrade took. For this reason, weekend or out of hours upgrades can be arranged.