> I want to retrieve all the photos from all the users of certain project. My > sql like query will be "select projectid * photos from Users". How can i run > this kind of row key predicate while executing query on cassandra? You cannot / should not do that using the data model you have. (i.e. you could do it with a secondary index, but in this case you probably should not).
Try to de-normalise your data. Say a CF called ProjectPhotos * row key is the project_id * column name is <timestamp:user_id> * column value is image_url or JSON data about the image. You would then slice some columns from one row in the ProjectPhotos CF. You then need to know what images a user has uploaded, with say the UserPhotos CF. * row key is user_id * column name is timestamp * column value is image_url or JSON data about the image. I did a twitter sample app at http://wdcnz.com a couple of weeks ago that shows denormalising data https://github.com/amorton/wdcnz-2012-site and http://www.slideshare.net/aaronmorton/hellow-world-cassandra Hope that helps. ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 17/08/2012, at 12:39 AM, Swathi Vikas <swat.vi...@yahoo.com> wrote: > Hi, > > I am trying to run query on cassandra cluster with predicate on row key. > > I have column family called "Users" and rows with row key like > "projectid_userid_photos". Each user within a project can have rows like > projectid_userid_blog, projectid_userid_status and so on. > > I want to retrieve all the photos from all the users of certain project. My > sql like query will be "select projectid * photos from Users". How can i run > this kind of row key predicate while executing query on cassandra? > > Any sugesstion will help. > > Thank you, > swat.vikas >>> >>> >> >> >> > > >
