prevent downstream nil exception when view_definition is nil.

[coldnebo]

Fixes #330. it looks like there is more than one way to collect column names, but I'm not sure what 'real' column names are in the context of schema_statements.rb#L253. Is my fix ok, or does it mask other issues?

[metaskills]

Not sure if guarding against these are a good idea. See:

• aecca5c
• Incorrect syntax near '-'.: EXEC sp_helptext sd-portal-person #73
• .find() method not working #140 (comment)

Not sure, but the general history I remember is that being silent on this core issue has caused more grieve than it saved.

[coldnebo]

The warn behavior in the fix for #73 is unchanged by this fix. However, if you are saying that it's better to warn the user during find() rather than silencing the downstream error, I agree.

It might be better to duplicate the warning here too.

[coldnebo]

What do you think of this approach?

[metaskills]

It might be better to duplicate the warning here too.

Yea, that might be the best way. Raising an error in both places caused issues with those that could not set permissions due to legacy and/or overzealous DBA's. Likewise, being silent has caused errors and confusion too. So connecting up a second warn that pointed to the first might be best.