в 13:45, 26 мая 2010

2010-05-26T13:45:56Z

Admin: 1 версия

2010-05-26T10:14:08Z

1 версия

Новая страница

==Get next sequence value==



<source lang="sql">

postgres=# -- Creation of a sequence
postgres=#
postgres=# CREATE SEQUENCE shipments_ship_id_seq START 200 INCREMENT 1;
CREATE SEQUENCE
postgres=#
postgres=# -- Select the next number from a sequence with the nextval() function:
postgres=#
postgres=# SELECT nextval ("shipments_ship_id_seq");
nextval
---------
200
(1 row)
postgres=#
postgres=#
postgres=# drop sequence shipments_ship_id_seq;
DROP SEQUENCE
postgres=#

</source>

==Get sequence last value and increment_by==



<source lang="sql">

postgres=# CREATE SEQUENCE myseq MINVALUE 0;
CREATE SEQUENCE
postgres=#
postgres=# SELECT last_value, increment_by FROM myseq;
last_value | increment_by
------------+--------------
0 | 1
(1 row)
postgres=#
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=#

</source>

==Get sequence next value==



<source lang="sql">

postgres=# CREATE SEQUENCE myseq MINVALUE 0;
CREATE SEQUENCE
postgres=# -- Incrementing a sequence
postgres=#
postgres=# SELECT nextval("myseq");
nextval
---------
0
(1 row)
postgres=#
postgres=# SELECT nextval("myseq");
nextval
---------
1
(1 row)
postgres=#
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=#

</source>

==Reference sequence value in insert statement==



<source lang="sql">

postgres=# CREATE TABLE employee (
postgres(# ID int,
postgres(# name varchar(10),
postgres(# salary real,
postgres(# start_date date,
postgres(# city varchar(10),
postgres(# region char(1)
postgres(# );
CREATE TABLE
postgres=#
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (1, "Jason", 40420, "02/01/94", "New York", "W");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (2, "Robert",14420, "01/02/95", "Vancouver","N");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (3, "Celia", 24020, "12/03/96", "Toronto", "W");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (4, "Linda", 40620, "11/04/97", "New York", "N");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (5, "David", 80026, "10/05/98", "Vancouver","W");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (6, "James", 70060, "09/06/99", "Toronto", "N");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (7, "Alison",90620, "08/07/00", "New York", "W");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (8, "Chris", 26020, "07/08/01", "Vancouver","N");
INSERT 0 1
postgres=# insert into employee (ID, name, salary, start_date, city, region)
postgres-# values (9, "Mary", 60020, "06/09/02", "Toronto", "W");
INSERT 0 1
postgres=#
postgres=# select * from employee;
id | name | salary | start_date | city | region
----+--------+--------+------------+-----------+--------
1 | Jason | 40420 | 1994-02-01 | New York | W
2 | Robert | 14420 | 1995-01-02 | Vancouver | N
3 | Celia | 24020 | 1996-12-03 | Toronto | W
4 | Linda | 40620 | 1997-11-04 | New York | N
5 | David | 80026 | 1998-10-05 | Vancouver | W
6 | James | 70060 | 1999-09-06 | Toronto | N
7 | Alison | 90620 | 2000-08-07 | New York | W
8 | Chris | 26020 | 2001-07-08 | Vancouver | N
9 | Mary | 60020 | 2002-06-09 | Toronto | W
(9 rows)
postgres=#
postgres=# -- Creation of a sequence
postgres=#
postgres=# CREATE SEQUENCE myseq START 200 INCREMENT 1;
CREATE SEQUENCE
postgres=#
postgres=# INSERT INTO employee (id)VALUES (nextval("myseq"));
INSERT 0 1
postgres=#
postgres=# select * from employee;
id | name | salary | start_date | city | region
-----+--------+--------+------------+-----------+--------
1 | Jason | 40420 | 1994-02-01 | New York | W
2 | Robert | 14420 | 1995-01-02 | Vancouver | N
3 | Celia | 24020 | 1996-12-03 | Toronto | W
4 | Linda | 40620 | 1997-11-04 | New York | N
5 | David | 80026 | 1998-10-05 | Vancouver | W
6 | James | 70060 | 1999-09-06 | Toronto | N
7 | Alison | 90620 | 2000-08-07 | New York | W
8 | Chris | 26020 | 2001-07-08 | Vancouver | N
9 | Mary | 60020 | 2002-06-09 | Toronto | W
200 | | | | |
(10 rows)
postgres=#
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=# drop table employee;
DROP TABLE
postgres=#
postgres=#

</source>

==Reference sequence value in table creation statement==



<source lang="sql">
postgres=# -- Creation of a sequence
postgres=#
postgres=# CREATE SEQUENCE myseq START 200 INCREMENT 1;
CREATE SEQUENCE
postgres=#
postgres=# CREATE TABLE shipments (
postgres(# id integer NOT NULL DEFAULT nextval("myseq"),
postgres(# customer_id integer,
postgres(# isbn text,
postgres(# ship_date timestamp);
CREATE TABLE
postgres=#
postgres=#
postgres=# drop table shipments;
DROP TABLE
postgres=# drop sequence myseq;
DROP SEQUENCE
postgres=#

</source>

← Предыдущая	Версия 13:45, 26 мая 2010
(нет различий)

PostgreSQL/Sequence/Sequence Value - История изменений

в 13:45, 26 мая 2010

Admin: 1 версия