sql to update existing database?

Hello there,

is there a script or Entity Modeller tool or whatever to generate a =
"diff" SQL for given model and existing database, so that tables get =
created for new entities, but updated (by adding columns) for the =
already existing ones?

Seems to me basic enough functionality for someone already have done =
that, but can't find anything on the web...

Thanks and all the best,
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Ondra =C4=8Cada
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