Examinethecode：CREATEROLEreadonlyIDENTIFIESUSINGapp.chk_readwrite；CREATEROLEreadwriteIDENTIFIEDUSINGapp.chk_readwrite；CREATEORREPLACEPROCEDUREapp.chk_readwriteAUTHIDCURRENT_USERISipchkSTRING（30）；BEGINIFsys_context（‘USERENV’，’ISDBA’）=’TRUE’THENDBMS_SESSION

Examinethecode：CREATEROLEreadonlyIDENTIFIESUSINGapp.chk_readwrite；CREATEROLEreadwriteIDENTIFIEDUSINGapp.chk_readwrite；CREATEORREPLACEPROCEDUREapp.chk_readwriteAUTHIDCURRENT_USERISipchkSTRING（30）；BEGINIFsys_context（‘USERENV’，’ISDBA’）=’TRUE’THENDBMS_SESSION.SET_ROLE‘READWRITE’）；ELSEDBMS_SESSION.SET_ROLE（‘READONLY’）；END；/WhichthreestatementscorrectlydescribetheSecureApplicationroledefinition？（）

A.Nouserorapplicationhastorememberorhideapassword.

B.ItpreventseveryoneexceptatrueDBAsessionfromacquiringtheREADWRITErole.

C.app.chk_readwriteiscalledwheneverausertriestoaccessrowsprotectedbytheREADONLYorREADWRITElabel.

D.app.chk_readwriteiscalledbyusersorapplicationswhentheywanttoenabletheREADONLYor READWRITErole.