Databases Reference
In-Depth Information
Technologies and Language
— Implemented in Erlang. Also, uses a bit of C and JavaScript.
Access Methods
— Interfaces for JSON (over HTTP) and protobuf clients exist. Libraries
for Erlang, Java, Ruby, Python, PHP, and JavaScript exist.
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Open-Source License
— Apache License version 2.
Who Uses It
— Comcast and Mochi Media.
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All three — Cassandra, Riak and Voldemort — provide open-source Amazon Dynamo capabilities.
Cassandra and Riak demonstrate dual nature as far their behavior and properties go. Cassandra has
properties of both Google Bigtable and Amazon Dynamo. Riak acts both as a key/value store and a
document database.
DOCUME NT DATABASES
Document databases are not document management systems. More often than not, developers
starting out with NoSQL confuse document databases with document and content management
systems. The word
document
in
document databases
connotes loosely structured sets of key/
value pairs in documents, typically JSON (JavaScript Object Notation), and not
documents
or
spreadsheets
(though these could be stored too).
Document databases treat a document as a whole and avoid splitting a document into its constituent
name/value pairs. At a collection level, this allows for putting together a diverse set of documents
into a single collection. Document databases allow indexing of documents on the basis of not only
its primary identifi er but also its properties. A few different open-source document databases are
available today but the most prominent among the available options are MongoDB and CouchDB.
MongoDB
Offi cial Online Resources —
www.mongodb.org
.
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History —
Created at 10gen.
Technologies and Language —
Implemented in C++.
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Access Methods —
A JavaScript command-line interface. Drivers exist for a number of languages
including C, C#, C++, Erlang. Haskell, Java, JavaScript, Perl, PHP, Python, Ruby, and Scala.
Query Language —
SQL-like query language.
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Open-Source License —
GNU Affero GPL (
http://gnu.org/licenses/agpl-3.0.html
).
Who Uses It —
FourSquare, Shutterfl y, Intuit, Github, and more.
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CouchDB
Offi cial Online Resources
—
http://couchdb.apache.org
and
www.couchbase.com
.
Most of the authors are part of Couchbase, Inc.
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History
— Work started in 2005 and it was incubated into Apache in 2008.
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