Databases tend to be forever evolving. Only very rarely are the structures within databases "static". That is, developers (either in-house, hired consultants or software providers) are constantly "improving" their applications. These improvements often require changes to the structure of the associated database. New objects are added, existing objects are removed, renamed or modified. As a database administrator, how do you know that what is in the databases that are "under your control"? As a developer, how can you be sure that the version of the database that you are working with agrees [logically] with version-n of the data model?
One solution is do not do any in-house development or integration! You can achieve this by buying a suite of integrated packages such as Oracle® Applications, PeopleSoft, SAP etc. Of course, your organization's pockets might not be that deep! Additionally, using packages "straight out of the box" is not always feasible. Packages do not always solve every problem (at least not without significant modification) and usually integration is required with other applications within the organization. So, for those situations where you are required to develop, modify and integrate, what do you do? How do you track the various versions of schemas?
In many situations, change is a way of life. Your organization's databases are exposed to continual change. Often, these updates come from multiple sources. For example, external software suppliers and in-house development teams may both develop their own applications and then provide integration components. During the development cycle, many instances of various schemas are created, updated and destroyed. These need to be tracked, versioned and managed. So who are you going to call?
As a database administrator, your developers will likely ask you questions like:
In order to resolve these issues you have to be able to achieve the following:
As a developer you might be concerned with what the DBAs are doing to "your" schemas. Suppose that the DBA team have been busily tuning and have now created a whole heap of additional indexes. They tell you, these are just "physical" changes! You guys [i.e. developers] don't need to know about these! Just make sure your upgrade scripts never fail [and of course make sure you never drop any of our changes [i.e. the changes that we never told you about]!
In a well disciplined environment, all changes are properly documented and are applied to all environments using appropriate change control procedures. Yep, I'm starting to lose you! You're muttering "It just doesn't happen like that in our organization!". But it can. All you need is a little discipline [no, make that lots of discipline] and a little help. This help is in the form of automated schema management tools.
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