Connecting Instant Client or Instant Client Light to an Oracle Database

Before you can connect Instant Client or Instant Client Light to an Oracle Database, ensure that the PATH environment variable specifies the directory that contains the Instant Client libraries.

• Specifying a Connection by Using the Easy Connect Naming Method
  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.
• Specifying a Connection by Configuring a tnsnames.ora File
  By default, when you install an Instant Client, Oracle Universal Installer does not include a sample tnsnames.ora file nor the Oracle Net Configuration Assistant utility normally used to create it.
• Specifying a Connection by Using an Empty Connect String and the LOCAL Variable
  Describes how to specify a connection to an empty connect string and set the LOCAL environment variable.