On 12/07/2019 17:49, Mark Rotteveel mark@...
[firebird-support] wrote:

> On 2019-07-12 15:15, Scott Morgan blumf@...
> [firebird-support] wrote:
>> Are NULLs considered values for unique constraints on a table?
>>
>> ...
>>
>
> The second attempt to insert null will fail if the other column has the
> same value. The behaviour of unique constraints and null is documented
> in:
>
> -
> https://firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-ddl-tbl.html#fblangref25-ddl-tbl-uqkey-nulls
> -
> https://firebirdsql.org/file/documentation/reference_manuals/user_manuals/html/nullguide-keys.html#nullguide-keys-uk
>

Ah, thank you, makes sense, and better still, works as I need it.

Scott