composite Unique constraint and null 2005-10-18 - By sandeep dubey
Hi,
I want to enforce a business rule on two columns such that col1, col2
should be unique. However for a given value of col1 nulls should be
allowed in col2. I can not implement that using a simple composite
unique constraint.
Eg.
create table foo(id number, name varchar2(10));
insert into foo values(1,1);
insert into foo values(1,1); -- should not be allowed
But following should be allowed
insert into foo values(1,null);
insert into foo values(1,null); -- should be allowed
Any ideas!!
Thanks
Sandeep
Sandeep
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