How to create id with AUTO_INCREMENT on Oracle?

Question

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

Answer 1

Starting with Oracle 12c there is support for Identity columns in one of two ways:

1. Sequence + Table - In this solution you still create a sequence as you normally would, then you use the following DDL:

   CREATE TABLE MyTable (ID NUMBER DEFAULT MyTable_Seq.NEXTVAL, ...)

2. Table Only - In this solution no sequence is explicitly specified. You would use the following DDL:

   CREATE TABLE MyTable (ID NUMBER GENERATED AS IDENTITY, ...)

If you use the first way it is backward compatible with the existing way of doing things. The second is a little more straightforward and is more inline with the rest of the RDMS systems out there.