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Introduction to Azure Cosmos DB

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Tags: database microsoft dbaas azure public-cloud cosmos-db
Clipped on: 2017-08-12

Welcome to Azure Cosmos DB

2017-7-14 3 min to read Contributors
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    MongoDB API - documents model

    Table API - key-value model

    Graph API - graph model

    Is it true that Azure Cosmos DB doesn't really support columnar/column-family data model in its commonly known meaning (despite stating so on various documentation pages)? Examples of columnar data model implementations to me would be Hadoop/Hbase, Cassandra, but I cannot find anything alike on in this documentation.

    The closest definition of columnar database that I could find is probably the following:

    Is it true then that by "columnar" you simply mean "whatever can be stored in tables can be stored in Azure Cosmos DB too"?


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Cosmos DB has a schema agnostic indexing engine capable of automatically indexing all the data it ingests without requiring any schema or secondary indexes from the developer. The engine relies on a set of logical index layouts (inverted, columnar, tree) which decouple the storage layout from the index and query processing subsystems. The paper (albeit a bit old) covers some of the ideas: Note the system has evolved significantly and the paper is out of date.

So yes, columnar is supported now because of the underlying engine, but we will have a formalized Cassandra and HBase API in the future. 

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@Bryan_King it's a proprietary database technology that is built on top of Service Fabric's ReliableQueues and ReliableDictionary that handles all the complexities of managing indexes for search capabilities for you.

The tools that are ReliableQueues and ReliableDictionary are the same tools that are the underpinnings of Sql Azure that allows the appearance of a traditional RDBMS while being absolutely nothing like the implementation of a RDBMS

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