A number of RDBMS help normal SQL sequences of some kind. The usual SQL syntax to create a sequence is:
The next is how you might fetch a worth from this sequence, utilizing jOOQ, assuming you’re utilizing the code generator:
// import static com.instance.generated.Sequences.*;
System.out.println(ctx.fetchValue(S.nextval()));
The sequence expression interprets to quite a lot of dialects:
-- CockroachDB, PostgreSQL, YugabyteDB
nextval('s')
-- Db2, HANA, Informix, Oracle, Snowflake, Sybase SQL Wherever, Vertica
s.nextval
-- Derby, Firebird, H2, HSQLDB, MariaDB, SQL Server
NEXT VALUE FOR s
You may as well embed the S.nextval() area expression in some other location the place a Area<?> may be situated, together with fetching the worth from inside a SELECT:
ctx.choose(S.nextval()).fetch();
Or, if you’ll want to fetch a number of sequence values in a single go, use nextvals():
System.out.println(ctx.fetchValues(S.nextvals(10)));
This prints one thing like:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
And the question being executed makes use of jOOQ’s GENERATE_SERIES emulation to fetch all of the values in a single go, e.g. for H2:
SELECT NEXT VALUE FOR s
FROM system_range(1, 10)
