How the database Target is named in EM12c

• If using the parameter 'db_unique_name' (for example, if using Data Guard) -  the discovered database name will be: db_unique_name.db_domain (if the parameter db_domain is not set, then just db_unique_name will be used)
• If not using db_unique_name, the format db_name.db_domain will be used (if the parameter db_domain is not set, then just the db_name will be used)
• If the names found in the discovery are not unique, a version number will be appended to the name. eg. orcl_1
• If the spfile<sid>.ora cannot be read (or cannot be converted to a pfile) the database target will assume the name <sid>_<hostname>
• If the database is discovered with the incorrect case, see Note:2024374.1"Enterprise Manager 12c discovers the Database Target name in Upper Case"