Schema Evolution

The changing of a schema (whether a database schema, or something as simple as the definition of a persistent class) over time. For data which is transient within a program, this is usually not a problem.

But for data which must persist, and which must be usable with newer versions of the software, it can be a big headache.

A couple of useful techniques:

And a few other points:

When encountering older data (using an older schema), several strategies exist on how to deal with it:

AnswerMe: Anybody wish to provide specific UseCases?
CategoryDatabase CategoryDataStructure

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