> > 2010/4/26 Roland Hänel <rol...@haenel.me>: > > Typically, in the SQL world we use things like AUTO_INCREMENT columns > that > > let us create a unique key automatically if a row is inserted into a > table. >
auto_increment is an antipattern; it adds an extra key which you don't need (usually). If your data has a natural candidate key, use that. If not, add extra parts until you have a unique key. If you are using OrderPreservingParitioner, it is really important to use keys which can give you a lexically sortable range to scan when you need to find them, so that you can use get_range_slice etc. There are other approaches however - in some cases it may be possible to use columns instead of rows there. But you'd still need keys for the columns. A straightforward way of generating unique IDs for your objects is to add an incrementing ID (managed locally) to the host name of the (client) node where they were generated. But this is probably not helpful in most cases. Mark
