If you erase tables from a database, then you exit Base and choose to *not* save, when you will reopen the database, you will notice that Base saved the database and you will not have the previously erased tables
I can confirm with Version: 4.4.3.0.0+ Build ID: 3eba5eb1774ab621a1f0f4dcc7e82cce6c025b0a TinderBox: Linux-rpm_deb-x86_64@46-TDF, Branch:libreoffice-4-4, Time: 2015-03-27_09:07:12 but I doesn't see this as bug, but enhancement - add warning to delete table dialog. Leaving unconfirmed for other opinion.
My guess is that this comes from a SHUTDOWN COMPACT instruction or something similar that is issued when the ODB document is closed ? I don't know whether this should be considered a bug or not. Adding devs to CC. @Lionel, what say you ?
SQL-commands are executed directly. You don't have to save a database if you change data, for example add a new row or delete a row. It is the same with deleting tables. You couldn't undo deleting a table. You could also detelte a table with SQL DROP TABLE "Tablename". This wouldn't be noticed by the GUI but it's the same SQL-Code, which is executed. GUI only noticed the chosen action from the contextmenue and recognizes there has somethin been changed. The only bug here seems to be: There hasn't been changed anything which could be saved with the "Save" button, but the button will be activated. Notice: It's the same while creating a table. You could create a table with GUI, but must not save the *.odb-file. The table would be there, if you reopen the file, because the SQL-code had been executed.
(In reply to robert from comment #3) > SQL-commands are executed directly. You don't have to save a database if you > change data, for example add a new row or delete a row. Yes, that's the design choice made with embedded HSQLDB. That choice can be debated, and I won't be among its defenders, but for now this is how things are.