Migrating Non-CDBs to New Hardware with a Different Endian Operating System and for a New Release Connecting to the Database with SQL*Plus 4 Connecting to the Database with SQL*Plus Connect to the Oracle Database instance using SQL*Plus. Step 1: Open a Command WindowTake the necessary action on your platform to open a window into which you can enter operating system commands. Step 2: Set Operating System Environment VariablesDepending on your platform, you may have to set environment variables before starting SQL*Plus, or at least verify that they are set properly. Step 3: Start SQL*PlusStart SQL*Plus. Step 4: Submit the SQL*Plus CONNECT CommandSubmit the SQL*Plus CONNECT command to initially connect to the Oracle database instance or at any time to reconnect as a different user.