How do I determine whether the connection mode of the oracle database is dedicated or shared?

How do I determine whether the connection mode of the oracle database is dedicated or shared?

This problem is related to the shared_servers and dispatchers parameters, as well as the TNSname. ora file on the server and client.

The shared_servers parameter on the DB side controls whether the server can accept the share server connection. However, the client can set to force DEDICATED in TNSname. ora.
See the following four cases:
DB shared_servers = 0, TNSname. ora server = shared or not set => DEDICATED connection
DB shared_servers = 0, TNSname. ora server = DEDICATED => DEDICATED connection
DB shared_servers> 0, TNSname. ora server = DEDICATED => DEDICATED connection
DB shared_servers> 0, TNSname. ora server = shared or not set => Shared connection