Connect to multiple database server by type of query (delete, insert, select, update)

I'd do it slightly different than Kilishan, in only that I wouldn't load all 4 connections in the constructor. I'd load them individually in the respective methods that they are used since each request will only need one connection.

Very true! I did mention that my example wasn't the best performance  It was intended as a concept, but you're absolutely correct that's the best way to handle it. 

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