fix: Models return type

[kenjis]

The return type of write-type query methods are not unified.
Failures of writing to database are abnormal things, so Exceptions should be thrown.

• change return type to void
• add query return value checks

If you forget to check an error, you’ll get silent bugs. Unchecked error values are worse than uncaught exceptions.
https://programmingduck.com/articles/exceptions-error-values

[MGatner]

IMO this is a deficiency of the framework that we are always working around. Being in the Exceptions camp I am definitely in favor of this 🤗 but glad to see that Lonnie approves as well.

[MGatner]

I still think we should find a way to handle this with model callback events so we can catch update() etc. That would solve the return typing.