yes, you are right, it depend on use cases. I suggested it is a better choice not only choice. JSON will be better if any filed change re-write whole data without reading. I tend to use JSON more, where my data does not change or very rarely, Like storing demoralized JSON data for analytic purpose. I prefer CF and [:scoped] method for frequently updating filed. { this.user.cart.category.p1.name:'' this.user.cart.category.p1.unit:'' this.user.cart.category.p1.desc:'' this.user.cart.category.p2.name:'' this.user.cart.category.p2.unit:'' this.user.cart.category.p2.desc:'' }
Yes you are right, Its really about understating app data and its behavior, not JSON or column, according to that designing DM. On Tue, Aug 28, 2012 at 12:20 PM, Guy Incognito <dnd1...@gmail.com> wrote: > i would respectfully disagree, what you have said is true but it really > depends on the use case. > > 1) do you expect to be doing updates to individual fields of an item, or > will you always update all fields at once? if you are doing separate > updates then the first is definitely easier to handle updates. > 2) do you expect to do paging of the list? this will be easier with the > json approach, as in the first your item may span across a page boundary - > not an insurmountable problem by any means, but more complicated > nonetheless. this is not > an issue obviously if all your items have the same number of fields. > 3) do you expect to read or delete multiple items individually? you may > have to do multiple reads/deletes of a row if the items are not adjacent to > each other as you cannot do 'disjoint' slices of columns at the moment. > with the json approach you can just specify individual columns and you're > done. again this is less of an issue if items have a known set of fields, > but your list of columns to read/delete may get quite large fairly quickly > > the first is definitely better if you want to update individual fields, > read-then-write is not a good idea in cassandra. but it is more > complicated for most usage scenarios, so you have to work out if you really > need the extra flexibility. > > > On 24/08/2012 13:54, samal wrote: > > First is better choice, each filed can be updated separately(write only). > Second you have to take care json yourself (read first-modify-then write). > > On Fri, Aug 24, 2012 at 5:45 PM, Roshni Rajagopal < > roshni.rajago...@wal-mart.com> wrote: > >> Hi, >> >> Suppose I have a column family to associate a user to a dynamic list of >> items. I want to store 5-10 key information about the item, & no specific >> sorting requirements are there. >> I have two options >> >> A) use composite columns >> UserId1 : { >> <itemid1>:<Name> = Betty Crocker, >> <itemid1>:<Descr> = Cake >> <itemid1>:<Qty> = 5 >> <itemid2>:<Name> = Nutella, >> <itemid2>:<Descr> = Choc spread >> <itemid2>:<Qty> = 15 >> } >> >> B) use a json with the data >> UserId1 : { >> <itemid1> = {name: Betty Crocker,descr: Cake, Qty: 5}, >> <itemid2> ={name: Nutella,descr: Choc spread, Qty: 15} >> } >> >> Which do you suggest would be better? >> >> >> Regards, >> Roshni >> >> This email and any files transmitted with it are confidential and >> intended solely for the individual or entity to whom they are addressed. If >> you have received this email in error destroy it immediately. *** Walmart >> Confidential *** >> > > >