Hi all, I posted a similar thread on stackoverflow - hope it's not repetitive for anyone here. Looking for better insight from the community on whether Cassandra is the right tool for me or not.
I am trying to understand some fundamentals in Cassandra, I was under the impression that one of the advantages a developer can take in designing a data model is by dynamically adding columns to a row identified by a key. That means I can model my data so that if it makes sense, a key can be something such as a user_id from a relational database, and I can for example, create arbitrary amounts of columns that relate to that user. What I'm not understanding is why there is so much emphasis to predefined columns in CQL examples, particularly in the CREATE TABLE/COLUMNFAMILY examples: CREATE TABLE emp ( empID int, deptID int, first_name varchar, last_name varchar, PRIMARY KEY (empID, deptID) ); Wouldn't this type of model make more sense to just stuff into a relational database? What if I don't know my column name until runtime and need to dynamically create it? Do I have to use ALTER TABLE to add a new column to the row using CQL? The particular app use-case I have in mind I would just need a key identifier and arbitrary column names where the column name might include a timestamp+variable_identifier. The whole point is that so I can see have extremely wide rows at the wonderful performance that Cassandra has to offer. As of right now, from everything I'm reading in regards to DataStax recommending CQL over Thrift (I think what I'm describing is possible with Thrift, but correct me if I'm wrong). That means I'd have to go AGAINST the recommendation to a protocol that's pretty much going to eventually not be supported. Is Cassandra the right tool for that? Are the predefined columns in documentation nothing more than an example? How does one add a dynamic column name with an existing column family/table? If I'm stuck with static columns, how is this any different than using a relational database such as postgres or mysql? What I found really powerful about Cassandra is being able to do something like the following in cassandra-cli which uses Thrift: SET mycf[id]['arbitrary_column'] = 'foo'; However, doing that in CQL isn't possible. Completely limits the way I was going to model my data for an application and would have no distinct advantage over a relational database. Please tell me I'm an idiot and/or am wrong and how I can make this work. It seems Thrift is the only solution, but I hate going against the recommended protocol. Thanks.
