Oracle Log File loss (ORA-O1109: Database not open) Solution

Oracle Log File loss (ORA-O1109: the database is not open) solution after deleting the oracle11g tablespace file by mistake, the database is not open the cause of the above problem is mistakenly put 'f: \ ORADB. DEF 'the data file is deleted. This deletion method is not normal. If the user and tablespace are deleted, then the data file is deleted, however, this operation only deletes the data file, and the user and tablespace are still there. Solution: 1) mount database: startup mount; 2) offline drop Data File: alter database datafile '<full_path_file_name> 'offline DROP; 3) open database: alter database open; ps: in this case, you can open the database again. 4) Delete the tablespace: ps: If it is accidentally deleted, you only need to recreate the tablespace. Action: SQL> startup mount ORA-01081: unable to start a running ORACLE-Close it first SQL> shutdown immediate ORA-01109: the database has not opened the detached database. The ORACLE routine has been disabled. The SQL> startup mount ORACLE routine has been started. Variable Size 167775108 bytes Database Buffers 436207616 bytes Redo Buffers 7135232 bytes Database load is complete. SQL> alter database datafile 'f: \ ORADB. DEF 'offline drop Fixed Size 1250428 bytes 2; the database has been changed. SQL> alter database open; the database has been changed. SQL> drop tablespace oradb including contents; The tablespace has been deleted.