Avoid errors on duplicated create table calls

[tetafro]

It might be easier for clients if CreateTable method didn't return an error when the table already exists. This way it can be safely put in service init code, and called each time on start.

@ucirello what do you think?

[ucirello]

Thanks for this PR and sorry for taking long to get back to you. I wish you had opened an issue before doing so.

I think this PR is BAD. This is making an explicit error now implicit. Knowing that a table is there is important for the backward compatibility ethos typical of the Go ecosystem.

I believe that the proper handling moving forward would be to return a strong error type for when the table is already there. And then add modifier parameter (self referencing option pattern) to skip the table creation if already present.

Would you be willing to reshape this PR?

[ucirello]

In any case, reopen as an issue first. Thank you.

[tetafro]

Sorry for not opening an issue, the code was short enough to just make a PR :)

I see your point, but I'm not sure about the details. For example, how can you say that it was a table creation error, if you can use any driver with UnsafeNew, therefore you can't get driver's typed error there?

Anyway, if you think that this feature is useful, it would be easier if you implement it the way you see it.