drop table patients;
create table patients (
   dba integer primary key,
   last_name varchar(40) not null,
   first_name varchar(40) not null,
   dob varchar(10) not null,
   sex varchar(2) not null,
   addr1 varchar(40) not null,
   addr2 varchar(40) not null,
   city varchar(40) not null,
   state varchar(40) not null,
   zip varchar(40) not null,
   mrn varchar(12) not null
);
