Run the Database Analyzer¶
Now you can use the section "Important actions" to compare the structure of your database with the expected structure. While in the previous step, tables and columns have been changed or added, this step now gives you the possibility to remove old and unneeded tables and columns from the database. Click "Compare current database with specification".
You will be able to execute queries to remove these tables and columns so that your database corresponds to the structure required for the new TYPO3 version.
Be aware if you have deliberately added columns and/or tables to your TYPO3 database for your own purposes! Those tables and columns are removed only if you mark them to be deleted of course, but please be alert that you don't delete them by mistake!
In the next step the changes you applied don't show up again. If you chose to delete some columns or tables, you will see that they have only been renamed. Now you can consider to let them be and delete them later when you're sure you're not going to need them. Or you can mark them again and drop them finally.
If you made TYPO3 apply all changes, you should after clicking "Execute" see a notice like this:
When you then click "Compare current database with specification" again and you only see the message
then all database updates have been applied.