Thread: Foreign key from another database

Hi,

Can I have a reference (with cascading), to another database? Let me
try to explain the situation a little better ;-)

I have a "main" database, clients. Then I have another database. Let's
call that program1. In program1 I have a table pTable and in clients I
have a table namned Client. Like this:

\c clients
CREATE TABLE Client (
CustId Serial PRIMARY KEY,
....
);

\c program1
CREATE TABLE pTable (
pId SERIAL PRIMARY KEY,
CustId INTEGER,
....
);

I would like the data to be dropped in pTable automatically, when the
client is deleted....

/ Antti

Antti Ijäs wrote:
> Can I have a reference (with cascading), to another database? Let me
> try to explain the situation a little better ;-)
>

You can write a trigger that uses functions from contrib/dblink to
execute a command in another database. However, without two-phase commit
support I don't think you can be sure the entire operation is atomic.

Joe

You might want to look into using multiple schemas in a single database
rather than multiple databases.

If you switch to the above, then you can do what you're looking for.
Postgresql has limited cross database abilities (contrib/dblink), but
not cross database foreign keys.

On Thu, 2003-04-03 at 04:16, Antti Ijäs wrote:
> Hi,
>
> Can I have a reference (with cascading), to another database? Let me
> try to explain the situation a little better ;-)
>
> I have a "main" database, clients. Then I have another database. Let's
> call that program1. In program1 I have a table pTable and in clients I
> have a table namned Client. Like this:
>
> \c clients
> CREATE TABLE Client (
> CustId Serial PRIMARY KEY,
> ....
> );
>
> \c program1
> CREATE TABLE pTable (
> pId SERIAL PRIMARY KEY,
> CustId INTEGER,
> ....
> );
>
> I would like the data to be dropped in pTable automatically, when the
> client is deleted....
>
> / Antti
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
>     (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
--
Rod Taylor <rbt@rbt.ca>

PGP Key: http://www.rbt.ca/rbtpub.asc

Use trigger on Client after delete, and dblink from contrib.

C.

Antti Ijäs wrote, On 4/3/2003 11:16 AM:
> Hi,
>
> Can I have a reference (with cascading), to another database? Let me
> try to explain the situation a little better ;-)
>
> I have a "main" database, clients. Then I have another database. Let's
> call that program1. In program1 I have a table pTable and in clients I
> have a table namned Client. Like this:
>
> \c clients
> CREATE TABLE Client (
> CustId Serial PRIMARY KEY,
> .....
> );
>
> \c program1
> CREATE TABLE pTable (
> pId SERIAL PRIMARY KEY,
> CustId INTEGER,
> .....
> );
>
> I would like the data to be dropped in pTable automatically, when the
> client is deleted....
>
> / Antti