All, recently I recovered a database where we lost the controlfile from the cold backup.I recreated the controlfile and then I was able to add the read only tablespaces with there corresponding datafile by doing some guesswork . But I was wondering if there is a right way of doing this . Here is the scenario . I appreciate any suggestions. scenario oracle 9.2.0.7 - cold backup available without the control file. - restored the cold backup and recreated the controlfile by taking all the datafiles. - there were 10 read only tablespaces having 15 datafiles out of a total of 247 datafile I dont know which datafiles belong to which read only tablespace and the user is hitting the below error java.sql.SQLException with message, ORA-00376: file 71 cannot be read at this time ORA-01111: name for data file 71 is unknown - rename to correct file ORA-01110: data file 71: '/u1/app/oracle/product/9.2.0/dbs/MISSING00071' what option I have to relate the these read only tablespace to there corresponding datafiles. Thanks in advance -Pk