Database Software

We've a table of 70gb ,every day around 10 gb data gets added to the table.
We are interested only last 7 days of data so every day night we've purging operation which deletes the data older than 7 days by comparing datetxn column value.

there are probkems by using purging activity,
1)purging takes lot of time.
2)job fails in the night then next day business impacts.

to overcome this probs we plan to convert the table to partitioned table by range with day wise partitions so that we can partition older than 7 days. we'll drop a partition of 7 days older and add a partition for the next day.

I've prepared a script to automate the drop partition , I need help to automate the add partition procedure,partition key column is a date datatype. If somebody done this already can you share the script with us to automate the partition addition.

DB version 10.2.0.3

Thanks in advance.