12c: PDB access through service
Hi,
With 12c, we can create a PDB (pluggable ) database, which is not an instance on its own.Therefore, client connections can only be made by using a service. The service is automatically created at PDB creation time and has the same name as the PDB. Please check Note 1607185.1 PDB: ORA-27101: Shared Memory Realm Does Not Exist While Connecting to Pluggable DB .