I do this daily. Use ASP.NET it' has special tools just for this. I would suggest you migrate all your data to one database first, or at least multiple databases of the same type. Trying to use 2 different database technologies in the same web app ids just insanely more complicated if it's even possible.

If you don't know how to write code, do not attempt this, hire a pro or buy "dummy" (no offense) software, ask us for a recommendation after you've migrated all data to one DB and will help you with that too. But we know which database you've chosen.

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Take a break and watch some stupid video clips