PostgreSQL/Cursor/Declare Cursor
Opens a transaction, declares the cur_publishers cursor, and closes it
<source lang="sql">
postgres=# CREATE TABLE "publishers" ( postgres(# "id" integer NOT NULL, postgres(# "name" text, postgres(# "address" text, postgres(# Constraint "publishers_pkey" Primary Key ("id") postgres(# ); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "publishers_pkey" for table "publishers" CREATE TABLE postgres=# postgres=# postgres=# insert into publishers values(150, "Can Press", "29 Ave. Toronto, ON"); INSERT 0 1 postgres=# insert into publishers values(91, "Henry Inc.", "115 Street New York, NY"); INSERT 0 1 postgres=# insert into publishers values(113, "O Inc.", "101 St, Sebastopol, CA"); INSERT 0 1 postgres=# insert into publishers values(62, "W Pubs", "1515, New York"); INSERT 0 1 postgres=# insert into publishers values(105, "N Press", "19 W, New York"); INSERT 0 1 postgres=# insert into publishers values(99, "A Inc", "375 St, New York"); INSERT 0 1 postgres=# insert into publishers values(101, "Z Inc", "375 Ave, New York"); INSERT 0 1 postgres=# insert into publishers values(163, "M Press", "PO Box 1215"); INSERT 0 1 postgres=# insert into publishers values(171, "B", "16 W. 18th St. New York"); INSERT 0 1 postgres=# insert into publishers values(102, "P Inc", "375 Hudson St, New York"); INSERT 0 1 postgres=# insert into publishers values(75, "D Inc", "1540 Broadway, New York"); INSERT 0 1 postgres=# insert into publishers values(65, "H Pubs", "10 E 53rd St, New York"); INSERT 0 1 postgres=# insert into publishers values(59, "R Inc", "1540 Broadway, New York"); INSERT 0 1 postgres=# postgres=# select * from publishers;
id | name | address
+------------+-------------------------
150 | Can Press | 29 Ave. Toronto, ON 91 | Henry Inc. | 115 Street New York, NY 113 | O Inc. | 101 St, Sebastopol, CA 62 | W Pubs | 1515, New York 105 | N Press | 19 W, New York 99 | A Inc | 375 St, New York 101 | Z Inc | 375 Ave, New York 163 | M Press | PO Box 1215 171 | B | 16 W. 18th St. New York 102 | P Inc | 375 Hudson St, New York 75 | D Inc | 1540 Broadway, New York 65 | H Pubs | 10 E 53rd St, New York 59 | R Inc | 1540 Broadway, New York
(13 rows) postgres=# postgres=# postgres=# --Opens a transaction, declares the cur_publishers cursor, and closes it: postgres=# postgres=# BEGIN; BEGIN postgres=# DECLARE cur_publishers CURSOR FOR SELECT * FROM publishers; DECLARE CURSOR postgres=# CLOSE cur_publishers; CLOSE CURSOR postgres=# postgres=# drop table publishers; DROP TABLE postgres=#
</source>
Using cursor in transaction
<source lang="sql">
postgres=# 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=# postgres=# BEGIN; BEGIN postgres=# DECLARE cur_employee CURSOR FOR SELECT id, name FROM employee; DECLARE CURSOR postgres=# FETCH FORWARD 2 IN cur_employee;
id | name
+--------
1 | Jason 2 | Robert
(2 rows) postgres=# -- Fetch backwards in the cur_employee cursor: postgres=# postgres=# FETCH BACKWARD 3 IN cur_employee;
id | name
+-------
1 | Jason
(1 row) postgres=# postgres=# END; COMMIT postgres=# postgres=# postgres=# postgres=# drop table employee; DROP TABLE postgres=# postgres=#
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