You way want to elaborate a bit about what you are trying to do. You meant
that your application should be able to handle a schema change in "real
time" ?

I would avoid to change the schema as part of an application normal flow. I
would likely use some data structure to store these as "metadata" (basically
each "extended property" would be stored as a row so that users can add new
properties without having to change tables schema).

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Patrice

Perhaps you'd better explain *why* the columns are being added to the
database schema during the execution of the application ...