remove all product and category items at once

gistfile1.txt

TRUNCATE TABLE `oxarticles`;
TRUNCATE TABLE `oxcategories`;
TRUNCATE TABLE `oxcategory2attribute`;
TRUNCATE TABLE `oxartextends`;
TRUNCATE TABLE `oxaccessoire2article`;
TRUNCATE TABLE `oxactions2article`;
TRUNCATE TABLE `oxobject2action`;
TRUNCATE TABLE `oxobject2article`;
TRUNCATE TABLE `oxobject2attribute`;
TRUNCATE TABLE `oxobject2category`;
TRUNCATE TABLE `oxobject2delivery`;
TRUNCATE TABLE `oxobject2discount`;
TRUNCATE TABLE `oxobject2group`;
TRUNCATE TABLE `oxobject2list`;
TRUNCATE TABLE `oxobject2payment`;
TRUNCATE TABLE `oxobject2selectlist`;
TRUNCATE TABLE `oxobject2seodata`;

http://forum.oxid-esales.com/showthread.php?t=6496&page=3#post141661