accessing data in drawings thru SQL?

Drawings *are* databases, so this is a database architecture question. It's going to come down to what kind of structures order the relevant information in the drawings, and do those structures order the data in ways significant and consistent. (Good luck.)

If you know what you are looking for in a drawing, you can automate searching a pile of drawings for that particular thing, but if they were created without imagining the extraction to another database, its unlikely that the drawings will contain structures in excess of what was deemed necessary by the draftsmen at the time. You might have more luck if the drawing generation process was automated to any great degree.

If by chance the files had title blocks that contained this information in the form of block attributes then this could be quite easily achieved using the attribute extraction tools, together with some batch processing routine. As Michael says, if the data's not easily templatable then you're just going to wind up extracting stuff almost arbitrarily that you won't know what to do with.

Could also be specific object types in specific places or on specific layers etc, but in my industry (architecture) drawing standards are so sloppy that it's safe to say that this would almost NEVER WORK.

I know that other industries are different, but how consistent, I can't say. I get drawings from say, manufacturers, and they are pretty sloppy too. (Fudged dimensions, incorrect layering, redundant styles, etc.) I've seen attempts to automate the production of drawings which might get around most of this, but the next question is, "what is an acceptable margin of error for your database extraction?". If it's near zero, I would find something else to do.