Re: Foreign keys, table inheritance, and TRUNCATE

[Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx>]

Florian Weimer wrote:
> Here's something I've just noticed:
> 
> CREATE TABLE foo (f INTEGER PRIMARY KEY);
> INSERT INTO foo VALUES (1);
> CREATE TABLE bar (b INTEGER REFERENCES foo);
> CREATE TABLE bar1 () INHERITS (bar);
> INSERT INTO bar1 VALUES (1);
> 
> This is quite correct:

No, it isn't; try leaving the first INSERT out:

alvherre=# CREATE TABLE foo (f INTEGER PRIMARY KEY);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "foo_pkey" for table "foo"
CREATE TABLE
alvherre=# CREATE TABLE bar (b INTEGER REFERENCES foo);
CREATE TABLE
alvherre=# CREATE TABLE bar1 () INHERITS (bar);
CREATE TABLE
alvherre=# INSERT INTO bar1 VALUES (1);
INSERT 0 1
alvherre=# select * from bar;
 b 
---
 1
(1 fila)

alvherre=# select * from foo;
 f 
---
(0 filas)

There is a bug here, but it's not in TRUNCATE.  FKs don't work with
inheritance.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.