Hate to be the one to point this out, but that is not the ideal use case for Cassandra.
If you really want to brute force it and "make it fit" cassandra, the easiest way is to create a class called Index. The index class would have name, phone and address fields. The hashcode and equals method would need to be overrided. Basically the same rules that apply to HashMap keys. Once you have that, you can use "if not exists" in the insert. Here's the risk though. What happens when the phone and address changes? The hashcode and equals will fail and queries will fail. This is a general anti-pattern for anything that uses Maps and is mutable. This is the reason the default object hashCode in java is system assigned and there's all sorts of warnings about overriding hashCode and equals. The only case where this works correctly is immutable databases or temporal databases. I would strongly advise against using a key that is a compound of name+phone+address. If the system needs to perform updates, the key needs to be immutable so that queries won't fail. On Sat, Feb 28, 2015 at 10:18 AM, Brian Sam-Bodden <bsbod...@integrallis.com > wrote: > As far as I know there is no such thing. You could make that value a > single PK for the table therefore guaranteeing uniqueness and check on > insert with `IF NOT EXISTS` to prevent dups. Of course that works just for > one value, if you have multiple values a compound PK will still let dups in > for a given column. So a different data model might be the answer there. If > the values in those columns can be enumerated then you could always create > a bitmask for the collection of values of the must-be-unique columns and > use that as park of your PK. If they ranges are too broad then maybe some > sort of hash made up of the values that need to be unique would be my next > attempt. > > You could also simply enforce the uniqueness programmatically but that > will require a read-before-you-write approach. Three is also the > possibility of using a Cassandra trigger (but I heard they are dangerous > and might not buy you anything more than the client-side programmatic > approach) > > Cheers, > Brian > http://integrallis.com > > On Fri, Feb 27, 2015 at 9:29 PM, ROBIN SRIVASTAVA < > srivastava.robi...@gmail.com> wrote: > >> I want to make unique constraint in Cassandra . As i want that all the >> value in my column be unique in my column family >> >> example : name-rahul ,phone-123, address-abc >> >> now i want that in this row no values equal to rahul ,123 and abc get >> inserted again on searching on datastax i found that i can achieve it by >> doing query on partition key as IF NOT EXIST ,but not getting the solution >> for getting all the three values unique means if >> >> name- jacob ,phone-123 ,address-qwe >> >> this should also be not inserted into my database as my phone column has >> the same value as i have shown with name-rahul. >> > > > > -- > Cheers, > Brian > http://www.integrallis.com >
