Fix placeholders being mapped to it's driver value instead of the value

[veloii]

This fixes #2568. I've also modified the SQLite prepared statement test to include a boolean placeholder.

[AndriiSherman]

Thanks a lot!
Could you please also add a few more test cases? We need to check if the same works for the update function in SQLite, and we need the same set of tests in the mysql.common and pg.common files.
If you don't have time for that, I can add those tests myself. Also, if you need any help, just ping me so I can guide you

[AndriiSherman]

cc @veloii

[veloii]

Sorry - I was out. I'll add the tests in now. How should they be named?

[AndriiSherman]

Sorry - I was out. I'll add the tests in now. How should they be named?

We can name it like: "insert: placeholders on columns with encoder", "update: placeholders on columns with encoder"

[veloii]

The set method on update doesn't allow placeholders. Is this a type bug or current limitation?

[AndriiSherman]

Oh, I guess it's a limitation, or maybe we can't even use it in updates. We'll need to check. For now, just skip update tests and focus only on inserts

[veloii]

Sorry for the delay, should all be done now! I was unable to verify the MySQL test locally but I assume the action will test it anyway.