SQL & PL/SQL

Hello Friends,

I have group of tables ( say tbl1, tbl2, tbl3,tbl4, tbl5 ) with same column name say x_type_cd .

I want to replace - ( hiphen ) characters of the column values with underscore (_) for all the tables..

select x_type_cd from tbl1;

abc
def
a-b
ab-c
abc-d


After replacing hyphen to underscore the data is ..

select x_type_cd from tbl1;

abc
def
a_b
ab_c
abc_d

Can any one suggest a solution for this ..
I want to have a script to implement this change.

thanks/kumar