Просмотр исходного текста страницы PostgreSQL/Inheritance/Select Inheritance

==Query inheritance table==



   
  <!-- start source code -->
   
    <source lang="sql">
postgres=#
postgres=# -- Inheritance
postgres=#
postgres=# CREATE TABLE cities (
postgres(#   name       text,
postgres(#   population real,
postgres(#   altitude   int
postgres(# );
postgres=#
postgres=# CREATE TABLE capitals (
postgres(#   state      char(2)
postgres(# ) INHERITS (cities);
CREATE TABLE
postgres=#
postgres=# SELECT name, altitude
postgres-# FROM cities
postgres-# WHERE altitude > 500;
 name | altitude
------+----------
(0 rows)
postgres=#
postgres=# SELECT name, altitude
postgres-#    FROM ONLY cities
postgres-#    WHERE altitude > 500;
 name | altitude
------+----------
(0 rows)
postgres=#
postgres=# drop table cities cascade;
NOTICE:  drop cascades to table capitals
DROP TABLE
postgres=#
           
       </source>
    
   


==Selecting with inheritance==



   
  <!-- start source code -->
   
    <source lang="sql">

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=# CREATE TABLE distinguished_authors (award text)
postgres-#               INHERITS (authors);
CREATE TABLE
postgres=#
postgres=# INSERT INTO distinguished_authors
postgres-#              VALUES (1,"S", "N", "Prize");
INSERT 0 1
postgres=#
postgres=# -- Selecting with inheritance
postgres=#
postgres=# SELECT * FROM distinguished_authors
postgres-#           WHERE last_name = "S";
 id | last_name | first_name | award
----+-----------+------------+-------
  1 | S         | N          | Prize
(1 row)
postgres=#
postgres=# SELECT * FROM ONLY authors WHERE last_name = "S";
 id | last_name | first_name
----+-----------+------------
(0 rows)
postgres=#
postgres=# drop table distinguished_authors;
DROP TABLE
postgres=# drop table authors;
DROP TABLE
postgres=#
           
       </source>