note 119404 added to sqlite3stmt.execute

From: Date: Sun, 29 May 2016 07:08:07 +0000
Subject: note 119404 added to sqlite3stmt.execute
Groups: php.notes 
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There's currently an issue in the SQLite3 PHP binding (not SQLite3 itself) that causes all queries to be executed twice. It has apparently existed for quite a while. See here for more info: https://bugs.php.net/bug.php?id=64531 Before discovering the above, I posted this: http://stackoverflow.com/questions/36617708/odd-behavior-with-sqlite3-non-select-prepared-transactions-and-fetcharray (includes copy-paste bug demo) Workaround: I strongly recommend wrapping any code that might run fetchArray() on non-SELECT query results inside a numColumns() check, like this: <?php $op = $db->prepare(...); $r = $op->execute(); // query #1 if ($r->numColumns()) { // returns column count, here being used as true/false test while ($row = $r->fetchArray(SQLITE3_ASSOC)) { // query #2 // your code here } } ?> To clarify: - Query #1 is where the SQLite3 query is executed the first time, query #2 is where the query is executed again. Yes, *everything* is executed twice; this is the bug. - If your code will only read from and not alter the database (so, a SELECT that won't cause database-altering triggers to run, for example), you're fine. Your query runs twice but it doesn't alter the result. - If your code will write to the database - for example an INSERT - you MUST not run fetchArray() (and execute the query again) if the number of columns is zero. - It's not documented in the manual but over here -http://php.net/manual/en/book.sqlite3.php#113144 - user 'bohwaz' mentions that there's also a SQLite3Stmt::readOnly() function since PHP 5.3.11 which will tell you if you just wrote to the DB. This is currently undocumented but might be a more appropriate alternative to numColumns() (I'm not sure what it does, it might be the same). You might prefer PDO for higher-volume work with SQLite3. This binding is ironically lighter-weight and provides direct access to some SQLite3-specific primitives and behavior... but it runs all queries twice. [[Note to moderators (this section may be deleted once it has been read; I'm also fine with feedback on the following): - Please don't consider this comment a bug report - I just want others to be aware of this issue so they don't have to bumble around for hours scratching their heads. :P - As of the submission date of this comment, there's a unapproved diff for this page stuck in DocBook so I can't add something like "due to bug #64531, you are recommended to wrap fetchArray() inside numColumns()...", which I think would carry more weight than this comment until this bug is fixed.]] ---- Server IP: 72.52.91.14 Probable Submitter: 110.146.182.182 ---- Manual Page -- http://php.net/manual/en/sqlite3stmt.execute.php Edit -- https://master.php.net/note/edit/119404 Del: integrated -- https://master.php.net/note/delete/119404/integrated Del: useless -- https://master.php.net/note/delete/119404/useless Del: bad code -- https://master.php.net/note/delete/119404/bad+code Del: spam -- https://master.php.net/note/delete/119404/spam Del: non-english -- https://master.php.net/note/delete/119404/non-english Del: in docs -- https://master.php.net/note/delete/119404/in+docs Del: other reasons-- https://master.php.net/note/delete/119404 Reject -- https://master.php.net/note/reject/119404 Search -- https://master.php.net/manage/user-notes.php

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