Using "LOCAL" environment variable

You can bypass using TNSNAMES by setting this environment variable on Windows. You can set this variable to the remote database connect string and SQL*Net would simply use this as connect string whenever user does not supply it. This environment variable is for WINDOWS only and it's equivalent in UNIX is TWO_TASK variable.

C:\>set LOCAL=ORA10G

C:\>sqlplus scott/tiger

SCOTT@ORA10G> select global_name from global_name;

GLOBAL_NAME
------------------------------------------------------------

ORA10G.REGRESS.RDBMS.DEV.US.ORACLE.COM

See the impact if its set to a wrong value

C:\>set LOCAL=ORA10

C:\>sqlplus scott/tiger

ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified

This variable has been there since long but has not been mentioned at many places so I thought it might be an useful post in my blog. Feel free to disagree ;)