Re: Updating cidr column with network operator

Axel Rau wrote:
> Hi SQLers,
> 
> I have a fk from address to network and try to update the foreign key 
> column to point at the network, "it belongs to":
> 
> CREATE TABLE network (
>   id      cidr     PRIMARY KEY     , -- 'PK, ,IPv4/6 Network address'
> )
> 
> CREATE TABLE address (
>   id         inet     PRIMARY KEY      , -- 'PK of IPv4/6 host address'
>   network cidr     NOT NULL            -- 'FK to Network table'
>                       REFERENCES network ON DELETE CASCADE ON UPDATE 
> CASCADE
> )
> 
> I tried (using the WHERE clause to eliminate the addresses were no 
> corresponding net exists):

But you can't insert a row in address w/o a valid network.id?  That's 
what the fk ensures.

Perhaps you could elaborate more?  Are you trying to *put* on the fk and 
you currently have bad data?

> UPDATE address
>     SET network = (SELECT N.id WHERE A.id << N.id)
>     FROM address A, network N
>     WHERE A.id << N.id;
> 

This also makes no sense.  For starters, << is "bitwise shift left" ...

> But this ended up with all network columns pointing at the same net (-:).
> Any help would be appreciated.
> 
> Axel
> Axel Rau, Frankfurt, Germany                           +49-69-951418-0
> 
> 
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-- 
Daryl

"We want great men who, when fortune frowns, will not be discouraged."    -- Colonel Henry Knox, 1776