Q:

Vertica - What happens with the projections when running the Database Designer?

What happens with the old(existing) projections when running the Database Designer?
For example:
I have a query file and need to make query-bases projections? If I run the DB designer would the old projecitons will be deleted, overwritten?

A:

You can specify what happens in the Database Designer wizard (not sure what they call it).
If you choose the "deploy" option it creates the new projections, refreshes them with data, and then deletes old projections it doesn't want the old ones. If you don't select that, it gives you some scripts you can run on your own that do the same thing.
I usually make Database Designer produce scripts. I look it over and then create my own scripts, based on those, that create and populate new projections. Once successful, I delete old projections on my own.
I may be overly cautious.

