Question

Apply this sql script:

create table software (
  id                        bigint not null,
  name                      varchar(255),
  description               varchar(255),
  constraint pk_software primary key (id))
;

create sequence software_seq;

Then this one:

alter sequence software_seq start with 1000;;

insert into software (id, name, description) values (  1, 'Soft1', 'Description1');

Then when insert new software programatically (from java), got new software with id = 24

Why not with 1001? Since ‘alter sequence software_seq start with 1000;’

Answer 1

You have a few things wrong here.

First of all, just creating a sequence with a particular name doesn’t attach it to the table and column that you want using it. You need to change software.id to use software_seq for default values:

alter table software alter column id set default nextval('software_seq');

and you’ll want to change the sequence’s ownership too (unless of course you’re using the sequence in other places):

OWNED BY table_name.column_name
OWNED BY NONE

The OWNED BY option causes the sequence to be associated with a specific table column, such that if that column (or its whole table) is dropped, the sequence will be automatically dropped as well. If specified, this association replaces any previously specified association for the sequence. The specified table must have the same owner and be in the same schema as the sequence. Specifying OWNED BY NONE removes any existing association, making the sequence “free-standing”.

So you should:

alter sequence software_seq owned by software.id;

Then when inserting, you’d either leave out the id:

insert into software (name, description) values ('...', '...');

or specify DEFAULT:

insert into software (id, name, description) values (default, '...', '...');

Your other problem is that start with doesn’t do what you think it does:

start

The optional clause START WITH start changes the recorded start value of the sequence. This has no effect on the current sequence value; it simply sets the value that future ALTER SEQUENCE RESTART commands will use.

If you want the sequence to start at 1000 then you can:

alter sequence software_seq restart with 1000;

Alternatively, you could use setval:

select setval('software_seq', 1000);

Of course, you could also use bigserial:

The data types smallserial, serial and bigserial are not true types, but merely a notational convenience for creating unique identifier columns (similar to the AUTO_INCREMENT property supported by some other databases). In the current implementation, specifying:

CREATE TABLE tablename (
    colname SERIAL
);

is equivalent to specifying:

CREATE SEQUENCE tablename_colname_seq;
CREATE TABLE tablename (
    colname integer NOT NULL DEFAULT nextval('tablename_colname_seq')
);
ALTER SEQUENCE tablename_colname_seq OWNED BY tablename.colname;

So using bigserial as the id column type would set up all the sequence stuff for you. Then you’d set the starting value as before using alter sequence or setval.