Require MaxLength property to be set for DataColumns of type string

[osudude]

The auto create process will throw an error if you have a datacolumn of type string and the max length is not set. Specfically, SelfLog just shows that it blew up during table auto creation but doesn't say why. I had to run a sql trace to see what it was blowing up. I had to run a sql trace to see the actual error:

"Line 2: Length or precision specification 0 is invalid."

Once you set the MaxLength property for the DataColumn the issue no longer happens. Would be nice if MaxLength property was required when column type is of type string.

[nblumhardt]

Thanks for the report! Sounds like an oversight. 👍

If anyone's able to send a PR, all help appreciated.

Unsure whether we should blow up in a more controlled manner, or just set some sensible defaults; probably the former.

[MV10]

Since my PR to split the project into Framework ConfigManager and Standard IConfig involves separating the DataColumn creation into a class shared between targets, I'll add exceptions for missing lengths (I assume that's what you mean by "blow up in a controlled manner").

I think true MAX can be changed by the DBA (or maybe just DBO, I've never had to do it), so in theory I don't think we could set a default with 100% safety without querying, which seems like overkill to me.

Maybe after the PR, this stops being a "bug" and becomes a "feature" request, in case exception is too severe? I haven't used auto-create (I'm a little surprised it's so popular), but I know my assumption would have been MAX on something like varchar before I thought about how to get that value.

[MV10]

The PR added an exception -- the enhancement angle is whether to provide sensible defaults (if it's even possible/reasonable).

[MV10]

Turns out a length of -1 is treated as MAX, so that case is covered.