Important: #98475 - Unsigned "pid" table columns
See forge#98475
Description
When upgrading to TYPO3 v12, the install tool database analyzer will change
the column field
pid of various tables to
UNSIGNED: They no longer
accept negative values.
Negative pids were needed until TYPO3 v10 in combination with workspaces, the Core nowadays only inserts rows with positive integers or 0 (zero) as pid value. An upgrade wizard took care of updating affected rows when upgrading to v10, current databases shouldn't contain such rows anymore.