# Read: Show real path in sys_file_storage
select name, uid, ExtractValue(configuration, '//T3FlexForms/data/sheet[@index="sDEF"]/language/field[@index="basePath"]/value') path from sys_file_storage where uid > 0 

# Write: Set a new value (in this case a detail pid) in FlexForm of a tt_news plugin
UPDATE tt_content SET pi_flexform = UpdateXML(pi_flexform, '//T3FlexForms/data/sheet[@index="s_misc"]/language/field[@index="PIDitemDisplay"]/value', CONCAT('<value index="vDEF">', 123, '</value>' )) WHERE uid=11107