title: Number or char for primary key column
body: <p>I'm building a database of a very important state institution. So far, for Primary Key columns I've sometimes used numbers, particularly int32 or int64, and sometimes I've used char but still I stored only numeric characters. Since this a very crucial task I have to make it both performance and comfort-wise efficient. Now I want to know,if it makes any difference to use number or char for a PK column considering the values in the char column will still be numeric characters.</p>
  
  <p>P.S.You might wonder what the point is in using char if I anyway store numeric characters. The reason is becuase the PK column is composed of many parts, like 3 characters for country, 3 characters for province,3 characters for city and 6 characters for a person. And besides that I can make string operations on those columns without worrying about explicit conversion.(I know there's implicit conversion in Oracle but it's discouraged to rely on it.)</p>