Is it safe to not parameterize an SQL query when the parameter is not a string?

Question

In terms of SQL injection, I completely understand the necessity to parameterize a string parameter; that\'s one of the oldest tricks in the book. But when can

Answer 1

When using a strongly-typed platform on a computer you control (like a web server), you can prevent code injection for queries with only bool, DateTime, or int (and other numeric) values. What is a concern are performance issues caused by forcing sql server to re-compile every query, and by preventing it from getting good statistics on what queries are run with what frequency (which hurts cache management).

But that "on a computer you control" part is important, because otherwise a user can change the behavior used by the system for generating strings from those values to include arbitrary text.

I also like to think long-term. What happens when today's old-and-busted strongly-typed code base gets ported via automatic translation to the new-hotness dynamic language, and you suddenly lose the type checking, but don't have all the right unit tests yet for the dynamic code?

Really, there's no good reason not to use query parameters for these values. It's the right way to go about this. Go ahead and hard-code values into the sql string when they really are constants, but otherwise, why not just use a parameter? It's not like it's hard.

Ultimately, I wouldn't call this a bug, per se, but I would call it a smell: something that falls just short of a bug by itself, but is a strong indication that bugs are nearby, or will be eventually. Good code avoids leaving smells, and any good static analysis tool will flag this.

I'll add that this is not, unfortunately, the kind of argument you can win straight up. It sounds like a situation where being "right" is no longer enough, and stepping on your co-workers toes to fix this issue on your own isn't likely to promote good team dynamics; it could ultimately hurt more than it helps. A better approach in this case may be to promote the use of a static analysis tool. That would give legitimacy and credibility to efforts aimed and going back and fixing existing code.