Transfering data between MySQL and Oracle databases

Create a database link from your Oracle server to the MySQL server.

Once the database link has been established, you can use the standard insert into.. select from syntax

insert into my_oracle_table  
select * from my_mysql_table@dblinkname
where date > sysdate - 7;

If you want to do this on a scheduled basis, use the job scheduler to schedule the transfer.

You can use O.D.I., Oracle Data Integrator.

http://www.oracle.com/technetwork/middleware/data-integrator/index.html

Oracle Data Integrator is a comprehensive data integration platform that covers all data integration requirements: from high-volume, high-performance batch loads, to event-driven, trickle-feed integration processes, to SOA-enabled data services.