One (of the many) good reasons to use the XMLDB editor in Moodle rather than hacking the db/install.xml file directly is that it warns you if you use a reserved name. For example:
Reserved text after [XML] in the screenshot is indicating that the word “column” is reserved and shouldn’t be used. It would be nice if it stopped you from saving such a change (it doesn’t) but at least it indicates a problem.
Reserved link points to the following location if you ever want to look up the currently used reserved words:
This link also shows you potential existing problems in your XMLDB that may need to be fixed.