Jerry Krinock <[EMAIL PROTECTED]> wrote: > My query: > > DELETE FROM `table1` WHERE (`id`=1 OR `id`=2 OR `id`=3 OR ... OR `id`=N) > > using the C API. When N exceeds 999, I get an error stating that the > maximum depth of 1000 has been exceeded, and this is documented in > http://www.sqlite.org/limits.html > , item 5. > > Of course, I could fix this by doing multiple queries when N>999, but > my code is very nicely encapsulated as is, and that change would make > it all yucky. So I'd like other alternatives.
The WHERE expression is parsed as follows: (...(((id=1 OR id=2) OR id=3) OR id=4) OR ...) OR id=N) If you draw this as a tree, you find that, indeed, it is N levels deep. But by explicit use of parentheses, you can force a balanced tree with a depth of only logN. (...((id=1 OR id=2) OR (id=3 OR id=4)) OR (...)...) But instead of all that trouble, why not just say: id IN (1,2,3,4,5,...,N) The latter is not only more efficient, but easier for human readers to understand as well. > > 1. I would describe my query as "1000 clauses wide". I'm not nesting > anything "1000 levels deep". Is there a way to rewrite my query and > make it work? > > 2. Documentation implies that I can change the parameter > SQLITE_MAX_EXPR_DEPTH from the default of 1000. But I can't find > SQLITE_MAX_EXPR_DEPTH in sqlite3.h. Seems to be neither a compiler > macro nor a global. (Mac OS X 10.5, sqlite 3.4.0). Where is it? > Look in sqliteLimit.h -- D. Richard Hipp <[EMAIL PROTECTED]> ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
