当查询返回非空结果集时，我们如何观察 sql 查询

Question

If we have a Java process that fires a query as select name from Person where id = '123' , and another process which inserts the record with the id 123 , how can the first process be notified when the record has been inserted?

Answer 1

I think you might want to have a look into Database Change Notification:

Database Change Notification is a feature that enables client applications to register queries with the database and receive notifications in response to DML or DDL changes on the objects associated with the queries. The notifications are published by the database when the DML or DDL transaction commits.

During registration, the application specifies a notification handler and associates a set of interesting queries with the notification handler. A notification handler can be either a server side PL/SQL procedure or a client side C callback. Registrations are created on all objects referenced during the execution of the queries. The notification handler is invoked when a transaction subsequently changes any of the registered objects and commits.

https://docs.oracle.com/cd/B19306_01/B14251_01/adfns_dcn.htm#BGBBHGAH