Re: constrain with MATCH full and NULL values in referenced table

On 8/12/19 8:11 AM, stan wrote:
> I am creating a table that has 2 values in it which are keys pointing to 2
> other tables. I need for the UNIQUE combination of these 2 keys to exist in
> a fourth table. It has been recommended to use a foreign key constraint with
> the MATCH FULL parameter.

Without the table schema it difficult for me to figure out what it is 
you are attempting.

See below for how MATCH FULL works:

https://www.postgresql.org/docs/11/sql-createtable.html

> 
> Here is my question, does this deal with NULLS in the 4th table? I am
> concerned that this constraint might fail to reject an entry if one, or both
> of the 2 key values being inserted in the table are NULLS,.
> 
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com