Online

It means that the Oracle database is running.
If the DoQuery attribute is set to 'true', the instance status is 'OPEN'.

Terminates the Oracle database service.
If there is an ongoing backup process, terminate it first.

Identify the Window Oracle Database Service Status. You see the results from this command:
C:W> SC STATUS SERVICE_NAME EX) SC STATUS OracleServiceORCL

If the DoQuery attribute is set to 'true', the Oracle database is still? running

DoQuery 속성이 True일 경우, 오라클 데이터베이스는 실행중이지만
인스턴스 상태가 'OPEN'이 아니거나 상태를 조회할 수 없는 상태를 응답없음으로 간주 합니다.

FaultOnQueryFailure 속성값이 true 면 응답없음 상태는 장애로 인식합니다. false면 응답없음 상태는 온라인 상태로 인식합니다.
If the FaultOnQueryFailure attribute is set to 'true', "no response" is handled as a trouble. If the FaultOnQueryFailure attribute is set to 'false',

Offline

It means that all the processes composing the Oracle database service are terminated.

Starts the Oracle database service.

C:\> SC START SERVICE_NAME EX) SC START OracleServiceORCL

If there is any ongoing backup process. If so, terminate it and try to open the instance again.

Identify the Window Oracle Database Service Status. You see the results from this command:
C:W> SC STATUS SERVICE_NAME EX) SC STATUS OracleServiceORCL\

 If the DoQuery attribute is set to 'true', Identify the OPEN state. 

Trouble

It means that it went offline from online without a termination process.

Starts the Oracle database service.

C:\> SC START SERVICE_NAME EX) SC START OracleServiceORCL

If there is any ongoing backup process. If so, terminate it and try to open the instance again.

Terminates the Oracle database service.
If there is an ongoing backup process, terminate it first.