It appears that there is no concept of AUTO_INCREMENT in Oracle, up until and including version 11g.
How can I create a column that behaves like auto increment in Or
Oracle Database 12c introduced Identity, an auto-incremental (system-generated) column. In the previous database versions (until 11g), you usually implement an Identity by creating a Sequence and a Trigger. From 12c onward, you can create your own Table and define the column that has to be generated as an Identity.
The following article explains how to use it:
Identity columns - A new entry in Oracle Database 12c