Automatically schema backup in Oracle
If you will have access to server's filesystem, or you can ask for this, you can use crontab utility. To verify whether you have access to cron, type in the following

crontab -e


If you will have an OS user,and if you can use the crontab utility to schedule a job, you can try something like this:

*/30 * * * * ~/bin/dump.bsh 1&gt;~/bin/log/dump.log 2&gt;&amp;1


This simple entry make a logical backup every half hour.
The dump.bsh file:

#!/bin/bash
PATH=/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:$ORACLE_HOME/bin
. $HOME/.bash_profile

now=`date +"%Y-%m-%d_%H-%M"`
expdp user/passwd directory=data_pump_dir dumpfile=lbackup$now.dmp schemas=schema_to_backup


You need to set Oracle env variables (here in the .bash_profile) since cron passes only a minimal set of env variables to your jobs.

Otherwise, go and have a look at this SQL Developer page. In the exports (expdp) section there is also a reference to automatic jobs.