On 12/07/2019 17:49, Mark Rotteveel m...@lawinegevaar.nl [firebird-support] wrote: > On 2019-07-12 15:15, Scott Morgan bl...@blueyonder.co.uk > [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
