CREATE TABLE sessions (
   SESSION_ID  bigint(20) NOT NULL auto_increment,
   SESSION_DATE    datetime,
   FILE_ARCHIVE    varchar (25),
   constraint pk_session PRIMARY KEY (session_id)
);

or to be MS Access Specific

CREATE TABLE sessions (
   SESSION_ID  bigint(20) NOT NULL AutoNumber,
   SESSION_DATE    datetime,
   FILE_ARCHIVE    varchar (25),
   constraint pk_session PRIMARY KEY (session_id)
);