What is the most appropriate repository for key value for a person with an RDBMS?

Question

Is there a great winner among all stores with key values? Cassandra, MongoDB, CouchDB? and do they all follow some central recommendations? or they all have their own opinions in defining their APIs.

I ask this question, especially from the point of view of a qualified RDBMS specialist, who is new to storages with key values. Which one should be followed in order to better understand the understanding / use of this field?

We know about RDMS from our theories that all available databases (Oracle, SQL Server, ..) will have all artifacts, for example. Tables, indexes, foreign keys, etc. The only difference in them is efficiency, safety, functions.

How can I learn about the universal theory of these document-oriented databases and what minimal artifacts will all of these databases have (Mongo, Couch, etc.)?

Answer 1

I'm working on MongoDB, so I'm biased, but I think this is a good combination of what you're used to with RDBMS (like dynamic queries and secondary indexes), as well as the performance and scalability of the -value store key.

Kassandra has a good distributed model, but afaik does not support secondary indexes. Supporting the Mongo and Couch document data models also makes it a little more complicated than using the Cassandra spreadsheet model.

Mongo Couch - . Couch map/reduce, . Mongo , , .