Re: TR: redundant constraint_schema

[Adrian Klaver <adrian.klaver@xxxxxxxxxxx>]

On 09/01/2018 09:27 AM, Andreas Kretschmer wrote:
> Am 01.09.2018 um 17:50 schrieb Olivier Leprêtre:
> > I notice that a new constraint "table1_col2_fkeyxxx" is created each 
> > time the previous ALTER TABLE ADD COLUMN is called
>
> smells like a bug.

Yeah, a quick test on a database where I have an event trigger:

create table fk_parent(col2 varchar primary key);
NOTICE:  Table public.fk_parent created
NOTICE:  caught CREATE TABLE event on 'public.fk_parent'
NOTICE:  caught CREATE INDEX event on 'public.fk_parent_pkey'


create table fk_child(col1 varchar references fk_parent(col2));
NOTICE:  Table public.fk_child created
NOTICE:  caught CREATE TABLE event on 'public.fk_child'
NOTICE:  caught ALTER TABLE event on 'public.fk_child'

\d fk_child
                   Table "public.fk_child"
 Column |       Type        | Collation | Nullable | Default
--------+-------------------+-----------+----------+---------
 col1   | character varying |           |          |
Foreign-key constraints:
    "fk_child_col1_fkey" FOREIGN KEY (col1) REFERENCES fk_parent(col2)

alter table fk_child add column if not exists col1 varchar references 
fk_parent(col2); 

NOTICE:  column "col1" of relation "fk_child" already exists, skipping 


NOTICE:  caught ALTER TABLE event on 'public.fk_child' 


ALTER TABLE

 \d fk_child
                   Table "public.fk_child" 


 Column |       Type        | Collation | Nullable | Default 


--------+-------------------+-----------+----------+--------- 


 col1   | character varying |           |          | 


Foreign-key constraints: 


    "fk_child_col1_fkey" FOREIGN KEY (col1) REFERENCES fk_parent(col2) 


    "fk_child_col1_fkey1" FOREIGN KEY (col1) REFERENCES fk_parent(col2) 



> Regards, Andreas


--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx