Creating a redaction policy when using partial redaction

In this recipe, you will implement partial redaction on columns of two different types: Number and Varchar2. Partial redaction means that only part (hence the name partial) of the data in a specified column will be masked (redacted), whereas the other part of the data will be visible to the user - for instance, the first 12 digits of credit card number will be redacted, whereas other 4 digits will be visible.

How to do it...

1. Log in to database as a user who has a DBA role (for instance, zoran):

   $ sqlplus zoran/oracle
   

2. Create a test table and insert some data in it:

   SQL> create table tbl (a number);
   
   SQL> insert into tbl values (123456);
   
   SQL> insert into tbl values (234567);
   
   SQL> insert into tbl values (345678);
   
   SQL> commit;

3. Create role (that is going to be used in redaction policy) and user usr1 as the first test user:

   SQL> create role myrole;
   
   
   SQL> create user usr1 identified by oracle1;
   
   
   SQL...