Thanks. But I think sometimes we need to do it, because by this way, we don't have to change the current CFs(assume we already have two CFs, and don't want to build a new one).
Alvin 2010/9/11 aaron morton <aa...@thelastpickle.com> > I cannot tell you where in the code to make these changes. But it sounds > like you want to fork cassandra and turn it into a RDBMS. It would > undoubtedly be easier to just use a RDBMS. > > Rather than have two CF's, address and name, just have one for the person > using a super CF. Pull back the entire row for the id. Denormalise your data > so the query is answered by one slice request to one CF, then you do not > need joins. > > If you want some advice on the data model, move the discussion to the user > list. > > Aaron > > > > On 11 Sep 2010, at 09:01, Alvin UW wrote: > > > Hello, > > > > I am going to build an index to join two CFs. > > First, we see this index as a CF/SCF. The difference is I don't > materialise > > it. > > Assume we have two tables: > > ID_Address(*Id*, address) , Name_ID(*name*, id) > > Then,the index is: Name_Address(*name*, address) > > > > When the application tries to query on Name_Address, the value of "name" > is > > given by the application. > > I want to direct the read operation to Name_ID to get "Id" value, then > go > > to ID_Address to > > get the "address" value by the "Id" value. So far, I consider only the > read > > operation. > > By this way, the join query is transparent to the user. > > > > So I think I should find out which methods or classes are in charge of > the > > read operation in the above operation. > > For example, the operation in cassandra CLI "get > > Keyspace1.Standard2['jsmith']" calls exactly which methods > > in the server side? > > > > I noted CassandraServer is used to listen to clients, and there are some > > methods such as get(), get_slice(). > > Is it the right place I can modify to implement my idea? > > > > Thanks. > > > > Alvin > >
