The isql ISQLPASSWORD environment variable allows you to set a default password for the current session. Therefore, you do not have to hard code a password into batch files.
If you do not specify a password with the /P qualifier, isql first checks for the ISQLPASSWORD variable. If no value is set, isql uses the default password, NULL. The following example sets the ISQLPASSWORD variable at the command prompt and then accesses the isql utility:
C:\>SET ISQLPASSWORD=abracadabra C:\> isql