In BaseX, all updates are performed on database nodes or in main memory. Update operations thus never affect the original input file. You can, however, use the [[Commands#EXPORT|EXPORT]] command or the fn:put() function to create an updated XML file.
Moreover changes in your database are propagated back to the original input file if the database option <code>[[Options#WRITEBACK|WRITEBACK]]</code> is turned on. This option can also be activated on [[Startup Command-Line Options#BaseX Standalone|command line]] via <code>-u</code>. Make sure you back up the original data before running your queries.
===Indexes===