Question

My app needs to know which row receives which key in the database.

I am using JDBC on read commited isolation level with batch updates. Therefore retrieving the keys with getGeneratedKeys isn’t possible. My plan is to fetch a Range of ids from the database in a transaction safe way, e.g. two parallel transactions can’t get the same keys.

Can I write some SQL-Query with the number of future rows as an argument to fetch a list of future keys in Oracle 11g?

What are my options here?

Answer 1

you can use sequences for this purpose:

create sequence s;

to retrieve a id

select s.nextval from dual;

or to retrieve a range of ids :

select s.nextval from dual connect by level <= 10;