Improve Mapping Logic

[mnavarrocarter]

I think mapping is a bit flaky and feels super hacky, and a lot of things are being pulled into the context to make it work. Maybe, when it gets that complicated is time to strip all that and simplify it with some help from userland.

I could add sqlType to the field metadata and have a predefined set of constants with all the known datatypes in all the drivers I support. And then a big ass mapper that will know how to map that based on the information passed by the user via the metadata.

It requires the user input, but then I'm sure I'll be able to handle that case properly. The only drawback is that the more platform/driver aware we do things, the more work is potentially needed if someone decides to migrate from, say MySQL to Postgres.

Anyway, overall I think I need to give mapping a second thought.