YourdatabaseisinARCHIVELOGmode.OnFridayevening，youperformanonlinedatabasebackupbyusingtheBACKUPDATABASEcommandattheRecoveryManager（RMAN）promptandclosethedatabase.OnMonday，theSystemAdministratorinformsyouaboutthefailureoftwoharddisks.Oneofthelostdiskscontainstwodatafiles，HR1.DBFandHR2.DBF，bothofwhichbelongtoaread/writetablespacenamedHR.Thediskalsocontainsadatafile，USERS.DBF，whichbelongstoaread/writetablespacenamedUSERS.YouneedtorestoreandrecoverthedatabasebackupthatwasperformedonFridayevening.Aftermountingthedatabase，youissuethefollowingRMANcommands：RMANRESTOREDATABASE；RMANRECOVERDATABASE；AftersuccessfullyexecutingtheseRMANcommands，youissuethefollowingstatementusingSQL*Plus：SQLALTERDATABASEOPEN；Youreceivethefollowingerrorswhenattemptingtoopenthedatabase：ORA-01157：cannotidentify/lockdatafile10seeDBWRtracefileORA-01110：datafile10：’D：\USERS.DBF’Whatisthecauseoftheseerrors？（）
YourdatabaseisinARCHIVELOGmode.OnFridayevening，youperformanonlinedatabasebackupbyusingtheBACKUPDATABASEcommandattheRecoveryManager（RMAN）promptandclosethe
database.OnMonday，theSystemAdministratorinformsyouaboutthefailureoftwoharddisks.Oneofthelostdiskscontainstwodatafiles，HR1.DBFandHR2.DBF，bothofwhichbelongtoaread/writetablespacenamedHR.Thediskalsocontainsadatafile，USERS.DBF，whichbelongstoaread/writetablespacenamedUSERS.YouneedtorestoreandrecoverthedatabasebackupthatwasperformedonFridayevening.Aftermountingthedatabase，youissuethefollowingRMANcommands：
RMAN>RESTOREDATABASE；
RMAN>RECOVERDATABASE；
AftersuccessfullyexecutingtheseRMANcommands，youissuethefollowingstatementusingSQL*Plus：
SQL>ALTERDATABASEOPEN；
Youreceivethefollowingerrorswhenattemptingtoopenthedatabase：
ORA-01157：cannotidentify/lockdatafile10seeDBWRtracefile
ORA-01110：datafile10：’D：\USERS.DBF’
Whatisthecauseoftheseerrors？（）