Connect Oracle database without tnsnames.ora from windows command prompt

-- Connect non sys user 

Syntax:

sqlplus <username>/"<password>"@<hostname>:<port#>/<database/servicename>

e.g.,
sqlplus system/"Passw0rd#"@example02:1521/testdb


e.g.,

C:\>sqlplus system/"Passw0rd#"@example02:1521/testdb

SQL*Plus: Release 12.1.0.2.0 Production on Tue Dec 18 12:31:53 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Last Successful login time: Thu Nov 15 2018 06:35:54 -05:00

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics, Real Application Testing
and Unified Auditing options

SQL>

-- Connect as sysdba

Syntax:
sqlplus <username>/"<password>"@<hostname>:<port#>/<database/servicename> as sysdba
e.g.,
sqlplus sys/"Passw0rd#"@example02:1521/testdb as sysdba

C:\>sqlplus sys/"Passw0rd#"@example02:1521/testdb as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Tue Dec 18 12:57:26 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics, Real Application Testing
and Unified Auditing options

SQL>