Client code. CQL will only deserialize composites as you mention in A.
On Sep 19, 2012, at 5:01 AM, "Roshni Rajagopal"
<roshni_rajago...@hotmail.com<mailto:roshni_rajago...@hotmail.com>> wrote:
Hi,
There was a conversation on this some time earlier, and to continue it
Suppose I want to associate a user to an item, and I want to also store 3
commonly used attributes without needing to go to an entity item column family
, I have 2 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}
}
Essentially A is better if one wants to update individual fields , while B is
better if one wants easier paging, reading multiple items at once in one read.
etc. The details are in this discussion thread
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Data-Modeling-another-question-td7581967.html
I had an additional question,
as its being said, that CQL is the direction in which cassandra is moving, and
there's a lot of effort in making CQL the standard,
How does approach B work in CQL. Can we read/write a JSON easily in CQL? Can we
extract a field from a JSON in CQL or would that need to be done via the client
code?
Regards,
Roshni
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