PostgreSQL/Postgre SQL/ROWTYPE

ROWTYPE assign through "select into"

postgres=#
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=# CREATE FUNCTION "get_data" (integer) RETURNS text AS "
postgres"#   DECLARE
postgres"#     -- Declare an alias for the function argument,
postgres"#     eid ALIAS FOR $1;
postgres"#     found_employee employee%ROWTYPE;
postgres"#   BEGIN
postgres"#     SELECT INTO found_employee * FROM employee WHERE id = eid;
postgres"#     RETURN found_employee.name || "" "" || found_employee.city;
postgres"#   END;
postgres"# " LANGUAGE "plpgsql";
CREATE FUNCTION
postgres=#
postgres=# select get_data(id) from employee;
     get_data
------------------
 Jason New York
 Robert Vancouver
 Celia Toronto
 Linda New York
 David Vancouver
 James Toronto
 Alison New York
 Chris Vancouver
 Mary Toronto
(9 rows)
postgres=#
postgres=# drop function get_data (integer);
DROP FUNCTION
postgres=# drop table employee;
DROP TABLE
postgres=#
postgres=#
postgres=#

Using the FOR loop with %ROWTYPE

postgres=#
postgres=#
postgres=# CREATE TABLE "books" (
postgres(#      "id"           integer NOT NULL,
postgres(#      "title"        text NOT NULL,
postgres(#      "author_id"    integer,
postgres(#      "subject_id"   integer,
postgres(#      Constraint "books_id_pkey" Primary Key ("id")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "books_id_pkey" for table "books"
CREATE TABLE
postgres=#
postgres=#
postgres=# insert into books values (7808,  "Java",                  4156, 9);
INSERT 0 1
postgres=# insert into books values (4513,  "Javascript",            1866, 15);
INSERT 0 1
postgres=# insert into books values (4267,  "C#",                    2001, 15);
INSERT 0 1
postgres=# insert into books values (1608,  "Oracle",                1809, 2);
INSERT 0 1
postgres=# insert into books values (1590,  "Sql Server",            1809, 2);
INSERT 0 1
postgres=# insert into books values (25908, "Postgre SQL",          15990, 2);
INSERT 0 1
postgres=# insert into books values (1501,  "Python",                2031, 2);
INSERT 0 1
postgres=# insert into books values (190,   "Java by API",             16, 6);
INSERT 0 1
postgres=# insert into books values (1234,  "2D",                   25041, 3);
INSERT 0 1
postgres=# insert into books values (2038,  "C",                     1644, 0);
INSERT 0 1
postgres=# insert into books values (156,   "C++",                    115, 9);
INSERT 0 1
postgres=# insert into books values (41473, "Programming Python",    7805, 4);
INSERT 0 1
postgres=# insert into books values (41477, "Learning Python",       7805, 4);
INSERT 0 1
postgres=# insert into books values (41478, "Perl Cookbook",         7806, 4);
INSERT 0 1
postgres=# insert into books values (41472, "Practical PostgreSQL",  1212, 4);
INSERT 0 1
postgres=#
postgres=# select * from books;
  id   |        title         | author_id | subject_id
-------+----------------------+-----------+------------
  7808 | Java                 |      4156 |          9
  4513 | Javascript           |      1866 |         15
  4267 | C#                   |      2001 |         15
  1608 | Oracle               |      1809 |          2
  1590 | Sql Server           |      1809 |          2
 25908 | Postgre SQL          |     15990 |          2
  1501 | Python               |      2031 |          2
   190 | Java by API          |        16 |          6
  1234 | 2D                   |     25041 |          3
  2038 | C                    |      1644 |          0
   156 | C++                  |       115 |          9
 41473 | Programming Python   |      7805 |          4
 41477 | Learning Python      |      7805 |          4
 41478 | Perl Cookbook        |      7806 |          4
 41472 | Practical PostgreSQL |      1212 |          4
(15 rows)
postgres=#
postgres=#
postgres=# -- Using the FOR loop with %ROWTYPE
postgres=#
postgres=# CREATE FUNCTION extract_title (integer) RETURNS text AS "
postgres"#   DECLARE
postgres"#
postgres"#      -- Declare an alias for function argument.
postgres"#     sub_id ALIAS FOR $1;
postgres"#
postgres"#      -- Declare a variable to hold book titles and set its default
postgres"#      --  value to a new line.
postgres"#     text_output TEXT :=""\n"";
postgres"#
postgres"#      -- Declare a variable to hold rows from the
postgres"#      -- books table.
postgres"#     row_data books%ROWTYPE;
postgres"#
postgres"#   BEGIN
postgres"#
postgres"#      -- Iterate through the results of a query.
postgres"#     FOR row_data IN SELECT * FROM books
postgres"#     WHERE subject_id = sub_id ORDER BY title  LOOP
postgres"#
postgres"#        -- Insert the title of a matching book into the text_output variable.
postgres"#       text_output := text_output || row_data.title || ""\n"";
postgres"#     END LOOP;
postgres"#
postgres"#       -- Return the list of books.
postgres"#     RETURN text_output;
postgres"#   END;
postgres"# " LANGUAGE "plpgsql";
ERROR:  function "extract_title" already exists with same argument types
postgres=#
postgres=#
postgres=# SELECT extract_title(2);
 extract_title
---------------
 Sql Server
(1 row)
postgres=#
postgres=#
postgres=# drop table books;
DROP TABLE
postgres=#
postgres=#

Using the %ROWTYPE attribute

postgres=#
postgres=#
postgres=# CREATE TABLE "authors" (
postgres(#      "id" integer NOT NULL,
postgres(#      "last_name" text,
postgres(#      "first_name" text,
postgres(#      Constraint "authors_pkey" Primary Key ("id")
postgres(# );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "authors_pkey" for table "authors"
CREATE TABLE
postgres=#
postgres=#
postgres=# insert into authors values (1111,  "Martin",       "Jason");
INSERT 0 1
postgres=# insert into authors values (1212,  "Worsley",      "Robert");
INSERT 0 1
postgres=# insert into authors values (15990, "Mathews",      "John");
INSERT 0 1
postgres=# insert into authors values (25041, "Smith",       "Williams");
INSERT 0 1
postgres=# insert into authors values (16,    "Alcott",       "May");
INSERT 0 1
postgres=# insert into authors values (4156,  "King",         "Stephen");
INSERT 0 1
postgres=# insert into authors values (1866,  "Herbert",      "Margaret");
INSERT 0 1
postgres=# insert into authors values (1644,  "Hogarth",      "Celia");
INSERT 0 1
postgres=# insert into authors values (2031,  "Brown",        "Wise");
INSERT 0 1
postgres=# insert into authors values (115,   "Poe",          "Allen");
INSERT 0 1
postgres=# insert into authors values (7805,  "Lutz",         "Mark");
INSERT 0 1
postgres=# insert into authors values (7806,  "Rice",         "Tom");
INSERT 0 1
postgres=# insert into authors values (1533,  "Black",        "Chris");
INSERT 0 1
postgres=# insert into authors values (1717,  "Brite",        "Linda");
INSERT 0 1
postgres=# insert into authors values (2112,  "Larry",        "Edward");
INSERT 0 1
postgres=# insert into authors values (2001,  "Clarke",       "Alison");
INSERT 0 1
postgres=# insert into authors values (1213,  "Green",        "Mary");
INSERT 0 1
postgres=#
postgres=# select * from authors;
  id   | last_name | first_name
-------+-----------+------------
  1111 | Martin    | Jason
  1212 | Worsley   | Robert
 15990 | Mathews   | John
 25041 | Smith     | Williams
    16 | Alcott    | May
  4156 | King      | Stephen
  1866 | Herbert   | Margaret
  1644 | Hogarth   | Celia
  2031 | Brown     | Wise
   115 | Poe       | Allen
  7805 | Lutz      | Mark
  7806 | Rice      | Tom
  1533 | Black     | Chris
  1717 | Brite     | Linda
  2112 | Larry     | Edward
  2001 | Clarke    | Alison
  1213 | Green     | Mary
(17 rows)
postgres=#
postgres=#
postgres=#
postgres=# -- Using the %ROWTYPE attribute
postgres=#
postgres=# CREATE FUNCTION get_author (integer) RETURNS text AS "
postgres"#   DECLARE
postgres"#
postgres"#     -- Declare an alias for the function argument,
postgres"#     -- which should be the id of the author.
postgres"#     author_id ALIAS FOR $1;
postgres"#
postgres"#     found_author authors%ROWTYPE;
postgres"#
postgres"#   BEGIN
postgres"#     SELECT INTO found_author * FROM authors WHERE id = author_id;
postgres"#
postgres"#     -- Return the first
postgres"#     RETURN found_author.first_name || "" "" || found_author.last_name;
postgres"#
postgres"#   END;
postgres"# " LANGUAGE "plpgsql";
CREATE FUNCTION
postgres=#
postgres=# -- Results of the new get_author() function
postgres=#
postgres=# SELECT get_author(1212);
   get_author
----------------
 Robert Worsley
(1 row)
postgres=#
postgres=#
postgres=# drop table authors;
DROP TABLE
postgres=#
postgres=#