Re: Undocumented behavior od DROP SCHEMA ... CASCADE - Mailing list pgsql-docs

From David G. Johnston
Subject Re: Undocumented behavior od DROP SCHEMA ... CASCADE
Date
Msg-id CAKFQuwZNS9YHs4xxgY3TEfHYP9fZjgsmuDn0+dLvD29k76=-sA@mail.gmail.com
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In response to Re: Undocumented behavior od DROP SCHEMA ... CASCADE  (Vik Fearing <vik@2ndquadrant.fr>)
Responses Re: Undocumented behavior od DROP SCHEMA ... CASCADE  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-docs
On Fri, Aug 12, 2016 at 8:54 AM, Vik Fearing <vik@2ndquadrant.fr> wrote:
On 12/08/16 14:47, Peter Eisentraut wrote:
> On 8/5/16 6:48 AM, denisa.cirstescu@asentinel.com wrote:
>> Page: https://www.postgresql.org/docs/9.5/static/sql-dropschema.html
>> Description:
>>
>> DROP SCHEMA ... CASCADE has a behavior that has not been documented.
>> According to the documentation: &quot;CASCADE - Automatically drop objects
>> (tables, functions, etc.) that are contained in the schema.&quot;.
>> Well, besides this, DROP SCHEMA ... CASCADE also drops all the views which
>> depends on the schema that is being dropped. It does not matter if the views
>> are in the public schema or another schema than the one being dropped, they
>> are deleted.
>
> Can you give an example?

vik=# create schema a create table t (id int);
CREATE SCHEMA
vik=# create schema b create view v as select * from a.t;
CREATE SCHEMA
vik=# drop schema a cascade;
NOTICE:  drop cascades to 2 other objects
DETAIL:  drop cascades to table a.t
drop cascades to view b.v
DROP SCHEMA

I think the OP is complaining that cascading to b.v is not sufficiently
documented.  It seems logical to me that this would be the correct
behavior, but since at least one person got confused enough about it to
come and tell us, we should probably add some kind of warning or something.

​Yeah, it should probably be modified to something like:

Automatically drop objects (tables, functions, etc...) that are contained in the schema.  Each object dropped is also done with the CASCADE option.  This means that others schemas will be affected if they depend on objects in the named schema.

David J.​

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