SQL & PL/SQL

This is the code:

create materialized view vw_sof as

select DISTINCT B.S_ID , A.RENEWAL_DATE,B.X_SCF,

         case when trunc(B.DFLT_END_DT- B.DFLT_START_DT) + 1 < = 365 THEN 365 

         ELSE trunc(B.DFLT_END_DT- B.DFLT_START_DT)   

          END SCF

     from VW_RENEWAL_DATE A ,TABLE_CONTRACT B

      WHERE B.S_ID = A.S_ID(+)

what changes has to be made in this code ,so that i refreshes for every 5 mins