In one of your databases, the user HR has the password HRMGR. You want to connect to a database instance whose listener listens on port 1531 by using this statement: CONNECT HR/HRMGR@orcl. No name server is used. Which statement is true about ORCL?

In Oracle Net Services, when a connect string of the format username/password@netservicename is used and no name server (like Oracle Internet Directory) is configured, the client attempts to resolve the netservicename using local naming methods. The primary local method is the tnsnames.ora file on the client machine. This file contains an entry for the net service name (orcl in this case) that maps it to a connect descriptor, which specifies the protocol, host, port, and service name for the connection.

A. orcl is a client-side alias (net service name). It can be, but does not have to be, the same as the actual database or service name.
C. orcl is a net service name, not a server hostname. The hostname is specified within the connect descriptor that orcl resolves to.
D. The name resolution occurs on the client initiating the connection, so the client's tnsnames.ora file is used, not the server's.
E. SERVICENAMES is a server-side initialization parameter that specifies the names for the database service; it is not a client-side parameter.

1. Oracle Database 23ai, Net Services Administrator's Guide, Chapter 5, "Configuring Naming Methods". It details the name resolution process, including the use of the tnsnames.ora file for local naming. Section "About Local Naming" states, "The local naming method stores net service names and their connect descriptors in a localized configuration file named tnsnames.ora."

2. Oracle Database 23ai, Concepts, Chapter 18, "Oracle Net Services". The section "Oracle Net Services Components" explains that Oracle Net uses connect descriptors to locate the network address of the server and identify the database service.