Behavior when topic type is deleted

Issue description

Currently the instances remain and have to be deleted seperately. If they are not connected to other topics, they can only be reached with their subject identifier, since their former type does not exist anymore.

Rejection comment

Quite complicated and takes unnecessary time during deletion. Created a system service to delete all insances of t topic type.

Reporting date

2015-08-25

Reported by

Robert Cerny

Rejection date

2021-02-08

Rejected by

Robert Cerny

Related to2

Remove the type instance table(Change)

Instances are deleted by deleting topic type(Change)

Work sessions

Start	2021-02-08T16:44:53
End	2021-02-08T17:59:14
Participant	Robert Cerny