Environment var.
LET v.SYS.ServerName = UPPER(ComputerName());
//storing environment name into a varibale
LET v.SYS.EnvironmentName = if(index('$(v.SYS.ServerName)','DV'),'dev connection string name',
if(index('$(v.SYS.ServerName)','UA'),'UAT connection string name' ));
LIB CONNECT TO $(v.SYS.EnvironmentName);