door locks

Model: 911 Carrera, Year:1988, Mileage:80000, Type of use:Street use only
If I Lock My Doors,Come Back Later And The Battery Is Now Dead Or The CEntral Looking System Has Failed,Can I Still Unlock The Doors With The Key? If Not How Do I Unlock The Doors Short Of Breaking A Window Or Calling A Locksmith Or Towing The Car To My Porsche Mechanic? Note:This Is Not The Question That I Just Previously Said Cancel. Thank You