On Thu, Oct 29, 2009 at 6:33 PM, satb <[email protected]> wrote: > > > > >> 2. How should we place constraints? For example, if I have a Users > table, > >> and one column is "login_name". How can I ensure that no two people > >> create > >> the same login name? Is there a constraint I can place or something > >> similar? > >> > > > > It has to be in your application. Nothing in hbase gives this feature > > afaik > > > > > In a multi threaded environment, how would two threads know if two users > are > creating the same username at the same time for insertion into the > database? > It surely doesn't seem like the application can control this behavior > except > through some synchronization mechanism (which wouldn't scale very well). > > > You can lock rows while writing to them.
> > >> > >> 4. For something not possible with HBase today, can I simply use the > >> MapReduce framework that comes with Hadoop over the HBase tables? > >> > > > > What do you mean? You can surely write MR jobs that talk to HBase but > > thats > > not a workaround to RDBMS kind of stuff. If you need RDBMS kind of > > functionality, maybe HBase is not for you. > > > > > >> > >> Thanks in advance > > > > > > I was reading that Streamy.com is running entirely on HBase. So isn't HBase > being promoted as suitable for OLTP type applications? > > In short, would an e-commerce website be capable of running entirely on > HBase? > > Streamy has a layer built on top of hbase that does the intelligent stuff for them. They can give you better insight into how they use it. Like I mentioned earlier too, HBase is good for denormalized data. If you want any of the SQL like features in real time, we dont have that. However, if you want to do batch processing, you can certainly write MR jobs to do almost anything. Also, you can look at frameworks like Cascading and Pig. Both of them can be made to talk to HBase. > > > -- > View this message in context: > http://www.nabble.com/HBase----unique-constraints-tp26123147p26123719.html > Sent from the HBase User mailing list archive at Nabble.com. > >
