PHP Knowledge Base Update -- July 2nd, 1999

Thanks to all those people who have made contributions to the knowledge base. Keep them coming! http://www.e-gineer.com/phpkb To help us get a feel for how the knowledge base is growing I have just added a statistics page: http://www.e-gineer.com/e-gineer/phpkb/stats.phtml Cheers, Nathan ------------------------------------------------------------ Where can I get PHPLIB? Does PHPLIB run on Windows NT? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/341 ------------------------------------------------------------ Vivek Awasthi PHPLIB can be found at: http://phplib.shonline.de You can download the tar.gz version, it works on all PHP platforms. On Windows NT you'll probably need WinZip to install it. Furthur instructions are well documented in it. ------------------------------------------------------------ My query succeeds, so why doesn't $db->f(field) in PHPLIB return anything? What is $db->next_record() used for in PHPLIB? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/343 ------------------------------------------------------------ Youngbong Choe In PHPLIB, next_record() gets the next row returned by the query. It basically just calls *_fetch_array(). If you do not call next_record() the fields are not available for accessing using f() and thus will return nothing. $q->next_record(); // use this method before $q->f() $id = $q->f("id"); You can get more information in the manual at: http://phplib.shonline.de ------------------------------------------------------------ When does Internet Explorer try to retrieve favicon.ico? Why do I get favicon.ico errors in my logs? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/345 ------------------------------------------------------------ Steven Champeon, Richard Davey When an Internet Explorer user bookmarks your site their browser automatically makes a request for favicon.ico. If it exists then this file is downloaded and placed as the icon next to your site in the users bookmarks list. IE4.x and 5.x have this "feature". Note that the favicon.ico action is /not/ limited to the root directory of a site - if the user bookmarks a page in a subdirectory, IE will try to fetch the icon from that directory as well. This may result in two file not found errors in your log files. If you want to reduce the number of errors or use a single favicon.ico file for your whole site then you might like to use a redirect in Apache: RedirectMatch permanent .*/favicon\.ico$ http://foo.com/your/file.ico This will sends all requests for favicon.ico to that location, regardless of what subdirectory they are made in. It should also be noted that Internet Explorer will download the file regardless of size. Don't name really large file favicon.ico! ------------------------------------------------------------ How can I fetch the field name and data for every row of a database query result? How can I get the column (field) name from a database query result row in MySQL? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/347 ------------------------------------------------------------ Fred Isler To work with fields in MySQL you need to know about the following functions: http://www.php.net/manual/function.mysql-num-fields.php3 http://www.php.net/manual/function.mysql-field-name.php3 Here is an example that will print the field names and their values from each row in a MySQL query result: <?php $dbh = mysql_connect("host", "foo1", "foo2"); mysql_select_db("foo3"); $query = "select * from foo"; $result = mysql_query($query, $dbh); $fields = mysql_num_fields($result); while ($row=mysql_fetch_array($result)) { for ($i=0; $i<$fields; $i++) { $name=mysql_field_name($result, $i); echo "$name = $row[$name]<BR>\n"; } echo "<br><br>\n"; } <? Should give you output like this: field1 = id1 field2 = blahblah field3 = done field1 = id2 field2 = blah field3 = doneagain (etc) ------------------------------------------------------------ Does MySQL support subselects? Can I do a subquery in a MySQL query? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/349 ------------------------------------------------------------ SANIsoft, Sander Pilon, Aaron Leon Kaplan Subselects will not be available in MySQL until version 3.23. To work around this you'll have to make multiple queries and create temporary tables to simulate subselect behaviour, or you'd have to come up with a 'flat' query that does the same. The general workaround (for all DBs where there are no subqueries) is temporary tables. First make a temp table for the subquery and then select from that. Below is an example that shows the original subselect query and the work around. Here is the query with subselect: SELECT bizname, contactphone, city, website, logo, description, discountid FROM business, discount WHERE business.bizid=discount.bizid AND discount.bizid IN (SELECT bizid FROM business WHERE catid=$categoryID) ORDER BY bizname Here is the work around: $subresult = mysql_query("SELECT bizid FROM business WHERE catid=$categoryID"); $num =mysql_Num_Rows($subresult); $i=0; $subcriteria=""; while ($i < m) { $subcriteria .= mysql_result($subresult,$i,"bizid"); $subcriteria .=","; $i++; } $subcriteria=substr($subcriteria,0,-1); / / Remove last comma $result = mysql_Query(" SELECT bizname, contactphone, city, website, logo, description, discountid FROM business, discount WHERE business.bizid=discount.bizid AND discount.bizid IN ($subcriteria) ORDER BY bizname"); ------------------------------------------------------------ How can I get today's date and time in PHP? How can I determine the current time in PHP? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/351 ------------------------------------------------------------ Sander Pilon Check the Date() and MkTime() functions. http://www.php.net/manual/function.date.php3 http://www.php.net/manual/function.mktime.php3 Leave the second argument in the Date() call empty to use today's date and time. mktime() returns the current time if you give no arguements at all. See the manual chapter 'Date and time functions' for more info: http://www.php.net/manual/ref.datetime.php3 ------------------------------------------------------------ How can I use a tab character as the delimiter in split() or explode()? How can I include a tab character in a string? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/355 ------------------------------------------------------------ Chuck Hagenbuch The tab character is available using the \t sequence. Remember that PHP will not interpret strings that are in single quotes so you must use double quotes for any string that contains a tab character. Here is an example of the use of tab as a delimiter for explode(): $foo = explode("\t", $array); ------------------------------------------------------------ How can I get the error message for a failed database operation? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/357 ------------------------------------------------------------ Chad Cunningham You can use the *_error() function to get the error message as reported by the database. You can use this directly in calls to die() to report the error easily. For example: mysql_select_db($dbname) or die(mysql_error()) For more information see the *_error() message for your database. http://www.php.net/manual/function.mysql-error.php3 ------------------------------------------------------------ Can I use PHP to interface with an AS/400 database? http://e-gineer.com/e-gineer/phpkb/view.phtml/qid/358 ------------------------------------------------------------ Rasmus Lerdorf AS/400 uses the DB2 database. You should be able to interface PHP to AS/400 using the DB2 ODBC driver.