I have deleted a database. I restored it again with a backup.
Now we lost some data of two days.
Is it possible to restore this lost data?

What database? What version? How much do you know about the database? How long until someone notices and finds out it was you?

MySQL database
I already reported it so everyone is informed.

Since you restored from a backup, I presume that was the last full backup? In other words, if you had a full backup from last night, it seems you would have chosen that. Then you would have only lost today's work.

So, do you have a database transaction log file? Or an incremental backup from last night?

If you provide more information, someone might be able to help. Or you might answer your own question. However, if you don't have the answers, and don't have a transaction log, then it's likely that you've simply lost the data (you're not running zfs snapshots or a NetApp with snapshots are you?).

The transactionlog option was not enabled. There also wasn't a backup from last night. The only thing I had was the backup from two days ago. So I was lucky with that. But isn't there a way to recover the data? It is still on the disk isn't it?

OK. So we know (and you know) what you are up against. It may or may not still be on disk. The system is live. The more it is used, and the less free space there is on the system, the more likely that the blocks will get re-used and the data over-written. Time is of the essence, and you have already lost too much time.

I haven't had to do the kind of recovery you are talking about. So someone else will have to give you some direction on this. The advice I know is that faced with such a situation, you should immediately stop using the system. Don't do anything until you have booted it off a CD with the recovery software or put the drive in another system where you have the recovery software. It seems you are unable to do that. Perhaps you can do something like dd the whole drive to another drive. Maybe an external mounted drive by firewire or usb? Then you may have a chance of recovering from that drive.