Comments on: Oracle’s Auto Incrementing with Sequences

By: Bastich

Bastich — Tue, 13 Apr 2010 16:56:16 +0000

Is there a simple example on how to use SEQUENCES in Oracle? I’m a complete newbie – and would like the syntax basics of how to query SEQUENCES.

Using “select MAXVALUE from some_sequence_table” is throwing
‘ORA-02201: sequence not allowed here’ error.

By: Matheus

Matheus — Wed, 17 Mar 2010 20:03:12 +0000

Oracle sequences are indeed superior to MSSQL Server IDENTITY method. But IMHO Oracle lacks a way to bind a sequence to a row, just as SERIAL data type wraps it all on PostgreSQL. When you CREATE TABLE SOME_TABLE (ID SERIAL), PostgreSQL internally gives you a sequence and beautifully sets its NEXTVAL to the ID column.

By: dnm

dnm — Tue, 10 Nov 2009 15:19:28 +0000

The downside to mysql, of course, is that it’s a steaming pile of crap.

By: suri

suri — Sun, 08 Nov 2009 08:14:19 +0000

As i faced one production issue in our environment, basically we created sequence number to generate the no in sequence but unfortunately we faced dupicate of sequence number,that means the sequence number has created duplicate .so pls share the view why the same sequence number got generated .

For ex

CREATE SEQUENCE supplier_seq
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;

By: Sarma K.M

Sarma K.M — Sun, 20 Sep 2009 16:06:02 +0000

what happens to the incrementor if i just run this query

select sequnce.next_val from dual;

By: rajiv lodha

rajiv lodha — Sun, 13 Sep 2009 19:59:57 +0000

how can i create a sequence which will increment in a random fashion?

create sequence semSeq
start with 156
increment by dbms_random.value(1,1000) num
nomaxvalue;

By: Oracle 10g: Using The Returning Clause With ADOdb : BorkWeb

Oracle 10g: Using The Returning Clause With ADOdb : BorkWeb — Tue, 21 Oct 2008 13:27:02 +0000

[...] when you are inserting into a table with auto incrementing values (via a sequence) you have always been able to grab the last value with a simple SELECT statement (line 22): PLAIN [...]

By: Rajesh

Rajesh — Sat, 06 Sep 2008 16:07:14 +0000

Its good,
i have a small doubt,
how to find the name of column where sequence is created?

Plz, forward to to my mail id rajesh227@gmail.com
tx, in advance

By: oldDog

oldDog — Mon, 21 Apr 2008 02:00:24 +0000

seqName.nextval and seqName.currval and their behavior have several advantages over AUTONUMBER or IDENTITY methods. For example, knowing the PK value to be used on INSERT before performing it saves on the cost of having to ask after the fact.

If you measure 1m executions of last_insert_id() after INSERT to a table, compared to use of seqName.nextval and seqName.currval and their costs, you may find a performance advantage for SEQUENCE. As for the practical matter of having to ask “what value did we get”, seqName.currval is there if you need it (until your next NEXTVAL!)

By: Joc

Joc — Wed, 20 Feb 2008 16:54:54 +0000

While your comments about MySQL being a much simpler way of doing things is true, there is a lot more flexibility with the Oracle approach. For example, if you wished to have an incrementing value that is shared by multiple tables but guaranteed unique across them all.