Обсуждение: is there a way to DROP foreign key constraint ?

I'm unable to find the complementary function to 

ALTER TABLE t ADD FOREIGN KEY(id) REFERENCES pkt(pk);

I would try DROP TRIGGER, but I've also been unable to 
find a way to name the constraint ;(


the built-in help is both inadequate and inconsistent
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amphora2=# \h alter table
Command:     ALTER TABLE
Description: Modifies table properties
Syntax:
ALTER TABLE table [ * ]   ADD [ COLUMN ] column type
ALTER TABLE table [ * ]   ALTER [ COLUMN ] column { SET DEFAULT value | DROP DEFAULT }
ALTER TABLE table [ * ]   RENAME [ COLUMN ] column TO newcolumn
ALTER TABLE table   RENAME TO newtable
ALTER TABLE table   ADD table constraint definition

amphora2=# \h create table
Command:     CREATE TABLE
Description: Creates a new table
Syntax:
CREATE [ TEMPORARY | TEMP ] TABLE table (   column type   [ NULL | NOT NULL ] [ UNIQUE ] [ DEFAULT value ]
[column_constraint_clause| PRIMARY KEY } [ ... ] ]   [, ... ]   [, PRIMARY KEY ( column [, ...] ) ]   [, CHECK (
condition) ]   [, table_constraint_clause ]   ) [ INHERITS ( inherited_table [, ...] ) ]
 

amphora2=# \h column_constraint_clause
No help available for 'column_constraint_clause'.
Try \h with no arguments to see available help.
amphora2=# \h column constraint definition
No help available for 'column constraint definition'.
Try \h with no arguments to see available help.
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On Fri, 20 Oct 2000, Hannu Krosing wrote:

> I'm unable to find the complementary function to 
> 
> ALTER TABLE t ADD FOREIGN KEY(id) REFERENCES pkt(pk);

Currently, ALTER TABLE ... DROP table constraint definition 
doesn't exist.

> I would try DROP TRIGGER, but I've also been unable to 
> find a way to name the constraint ;(

Umm, put the constraint name in the table constraint definition?
From the SQL spec:<table constraint definition> ::= [ <constraint name definition> ] <table constraint> [ <constraint
attributes>]<constraint name definition> ::= CONSTRAINT <constraint name>
 

Currently, you need to drop the three triggers from pg_trigger
that are associated with the constraint.  Easiest way to find
them if you don't have a constraint name is to look at the tg_args.

Stephan Szabo wrote:
> 
> On Fri, 20 Oct 2000, Hannu Krosing wrote:
> 
> > I'm unable to find the complementary function to
> >
> > ALTER TABLE t ADD FOREIGN KEY(id) REFERENCES pkt(pk);
> 
> Currently, ALTER TABLE ... DROP table constraint definition
> doesn't exist.
> 
> > I would try DROP TRIGGER, but I've also been unable to
> > find a way to name the constraint ;(
> 
> Umm, put the constraint name in the table constraint definition?
> >From the SQL spec:
>  <table constraint definition> ::=
>   [ <constraint name definition> ]
>   <table constraint> [ <constraint attributes> ]
>  <constraint name definition> ::= CONSTRAINT <constraint name>

Thanks! I was missing the CONSTRAINT word in <constraint name
definition>

------------
Hannu