Since Oracle Linux 7 is based on Red Hat Enterprise Linux (RHEL) I suppose it use
yum as package manager. Then you could give a look at yum-cron package,
yum-cron is an alternate interface to yum that is optimised to be
convenient to call from cron. It provides methods to keep repository
metadata up to date, and to check for, download, and apply updates.
check if it is present in your repositories:
yum list yum-cron
However, if it is a production server, I suggest to first evaluate the pros and cons of automatically updates. You can read this post to start.
Note that with
yum-cron it is also possible to just automatically download the updates (no istallation), and in case send a notification email to the sysadmin, and let him/you evaluate if it is the case to install them or not.
OP solution (reporting here the comment) : the package
yum-cron was available after enabling