You can specify a connection address to an Oracle Database directly from a client application, without having to configure a
tnsnames setting for the Instant Client.
This method is convenient in that you do not have to create and manage a
tnsnames.ora file. However, your application users must specify the host name and port number when they want to log in to your application.
For example, suppose you are running SQL*Plus on the client computer and want to connect to the sales_us database, which is located on a server whose host name is shobeen and port number is 1521. If you launch SQL*Plus from the command line, then log in as follows:
Similarly, in your application code, you can use Oracle Call Interface net naming methods to create the Instant Client-to-Oracle Database connection. For example, the following formats in the OCIServerAttach() call specify the connection information:
Specify a SQL connect URL string using the following format:
Alternatively, specify the SQL connect information as an Oracle Net keyword-value pair. For example:
“(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp) (HOST=shobeen) (PORT=1521))