The problem: retrieve one value from a query, if there is no matching row return a default.
Method 1: use for-each-row, overwrite the default with found values Method 2: use first-result, on exception return the default Method 3: use fold-row (wasn't an option when I first wrote the code) My question is, which of these is the "right" way to do what I want? Is there another, better, way? Note that method #2 has problems in my program but it might be due to my using chicken 4.10 (for now). ==additional details== Method 1, for-each-row, was my original approach and seemed to work fine. Then, in the midst of a major rewrite I tried to use first-result. It seemed odd to me to use an exception this way but I assumed (wrongly?) it was a fancy software engineery way to do things since the sqlite3 egg did not provide any direct way to do what I want. However I hit a strange scalability issue with database locks happening only a few hours into a run. After a lot of fruitless debug and on a hunch, I replaced the first-result with a for-each-row and now am able to run ten of thousands of tests over many hours (still not perfect, work progresses). I plan to replace use of for-each-row with something like: (define (get-id db name default) (fold-row (lambda (row) (car row)) #f db "SELECT id FROM tests WHERE testname=?" name)) Thanks.