sqlplus connect without typing the @local_SID when only have one instance Every time I want to connect with a user in Sqlplus I have to specify the database|sid name too,

SQL&gt;connect scott/tiger@orcl


I have installed another database for other purpose but I removed it.
Before the installation of second database I could connect without using @orcl but after I removed it I have to connect that way I said.
How can I fix this issue?
What OS are you using?

Check what the environment ORACLE_SID is set to.  Change it to the existing one and you won't be needing to specify the connection string anymore.