Switching NULL status

Hi All, Question, Is there a way to set up, if (on the same table) column1 is null than column2 must have a value and if column2 is null then column1 must have a value? Would I use a constraint? If so, how might I go about this. If not, any suggestions. Thanks in advance. Marco Sent via Deja.com http://www.deja.com/ Before you buy.

<mdelerme@my-deja.com> wrote in message news:8li6fg$624$1@nnrp1.deja.com... > Hi All, > > > Question, Is there a way to set up, if (on the same table) column1 is > null than column2 must have a value and if column2 is null then column1 > must have a value? Would I use a constraint? If so, how might I go > about this. If not, any suggestions. Thanks in advance. > create table a ( c1 integer, c2 integer); alter table a add constraint check ((c1 is null and c2 is not null) or (c1 is not null and c2 is null))constraint ck_switching_null; Regards, Roman Zarzecki rzarzecki@gis.com.pl