I'd say remove it. There is plenty other ways of keeping a copy of the old database.

Having said that we should problem warn users that the database will be over written.

@ciar4n it's not (me thinks)

Can we detect if tables with the same prefix exist, and if so asking if the user wants to keep them or not?

Can we detect if tables with the same prefix exist, and if so asking if the user wants to keep them or not?

Yes, once we promise-fy the client side, this would be easier (and is kinda our target) to achieve

I have explained here why we do need this feature back as it does not only concerns Advanced users.
#18797 (comment)

I can only assume that in the intervening time the code has been changed and is no longer relevant.

If you try to install joomla on an existing database with an existing database prefix then the existing tables are renamed to bak_prefix_tablename

@franz-wohlkoenig this can be closed

But if the tables belong to another installation they should not be renamed.

no different to today with joomla 3

The only way that would happen would be if

1. you manually chose the same prefix - backup created - no change to today
2. the random prefix used for site 1 is the same random prefix as used for site 2. Almost never going to happen but as a safety measure a backup is created.

So what is the problem you want to solve?

Wasn't the plan to make the installer more simple? Normally you should never install 2 or more joomla installations into one database. The only reason why we have prefixes is because mysql does not support schemas and you often only get one database from the hoster... so in the end it's a workaround for a infrastructure problem out of scope of joomla...

Anyway if we make auto backups if there is a installation it would be fine for me, hopefully the user get an information that his old database get backuped.

Can be reopened if needed.

Should this not be leaved open to at least make sure we inform the user what happened

Normally you should never install 2 or more joomla installations into one database.

That's true for experienced users, but the plan is also to increase usability, so your recommendation to inform the user is for me mandatory.

Something like

• "We found another Joomla database tables in this database, for security reasons we recommend to... (...) "
• "We found another Joomla database with the same prefix (...) if you click on continue the old tables will be backed up"
  Kind of...

Again - there is no change in behaviour to joomla 3 - its just that the backup is automatic now and not left to the user

Yes, I got you. Anyway we can improve the User Experience and lead them and inform them what is happening there.

Notifying the user should really be done. Silently moving an old database would be a bad experience. If someone writes a PR which include a decision before it get moved it would be ok to but only if needed and not always shown.

the code to remove old database or backup old database is still there. just a ui not present so easy to add it.

Yes, we could introduce an Ajax call to check for existing tables and then display a warning message that the tables exist and will be renamed, requiring further action from the user and... Or we introduce a message below the prefix field and thus close this issue, since we have a PR with #39215. If someone feels the need to change this, they can do this in the future, but we don't have to keep an issue open for 5 years without any solution. Anyway, thanks for the report and the discussion, I hope this solves the issue sufficiently.

Please do not close issues because there is no solution. An issue that is 5 years old should even get higher priority when there is still no solution.

I created a solution in the PR I linked.

Ok, why did you write "but we don't have to keep an issue open for 5 years without any solution."

Because if no one wants to do the totally proper solution with the AJAX call and all that stuff, then I'd rather provide the simple, not perfect solution and close a 5 year old issue, than keeping it open for yet another 5 years.

Fair enough ok!