Happy 4th of July!
In the 12c new feature a day series, I discussed the “Identity Column” feature yesterday. Extension to that feature is now you can use sequence pseudo-column NETXTVAL or CURRVAL as DEFAULT value for a column in table definition. In the prior releases to be able to do this, a trigger and some coding was required…
If the sequence is owned by another user, appropriate access should be granted on the sequence [privilege, synonym, qualify with schema name].
You can have only one IDENTITY column per table, buy you may create more than one column with DEFAULT sequence values.
Example:
CREATE TABLE T1 ( X1 NUMBER DEFAULT SCOTT.MYSEQ.NEXTVAL, X2 VARCHAR2);