NoSQL
A NoSQL database provides a mechanism for storage and retrieval of data that employs less constrained consistency models than traditional relational databases. Motivations for this approach include simplicity of design, horizontal scaling and finer control over availability. NoSQL databases are often highly optimized key–value stores intended for simple retrieval and appending operations, with the goal being significant performance benefits in terms of latency and throughput. NoSQL databases are finding significant and growing industry use in big data and real-time web applications. NoSQL systems are also referred to as "Not only SQL" to emphasize that they may in fact allow SQL-like query languages to be used.
History
Carlo Strozzi used the term NoSQL in 1998 to name his lightweight, open-source relational database that did not expose the standard SQL interface.[1] Strozzi suggests that, as the current NoSQL movement "departs from the relational model altogether; it should therefore have been called more appropriately 'NoREL'.[2]
Eric Evans (then a Rackspace employee) reintroduced the term NoSQL in early 2009 when Johan Oskarsson of Last.fm wanted to organize an event to discuss open-source distributed databases.[3] The name attempted to label the emergence of a growing number of non-relational, distributed data stores that often did not attempt to provide atomicity, consistency, isolation and durability guarantees that are key attributes of classic relational database systems.[4]
Taxonomy
There have been various approaches to classify NoSQL databases, each with different categories and subcategories. Because of the variety of approaches and overlaps it is difficult to get and maintain an overview of non-relational databases. Nevertheless, the basic classification that most would agree on is based on data model. A few of these and their prototypes are:
- Column: HBase, Accumulo
- Document: MongoDB, Couchbase
- Key-value : Dynamo, Riak, Redis, Cache, Project Voldemort
- Graph: Neo4J, Allegro, Virtuoso
Classification based on data model
Stephen Yen in his blog post "NoSQL is a Horseless Carriage" suggests the following:[5]
Term | Matching Database |
---|---|
KV Store | Keyspace, Flare, SchemaFree, RAMCloud, Oracle NoSQL Database (OnDB) |
KV Store - Eventually consistent | Dynamo, Voldemort, Dynomite, SubRecord, Mo8onDb, DovetailDB |
KV Store - Hierarchical | GT.m, Cache |
KV Store - Ordered | TokyoTyrant, Lightcloud, NMDB, Luxio, MemcacheDB, Actord |
KV Cache | Memcached, Repcached, Coherence, Hazelcast, Infinispan, EXtremeScale, JBossCache, Velocity, Terracotta |
Tuple Store | Gigaspaces, Coord, Apache River |
Object Database | ZopeDB, DB40, Shoal |
Document Store | CouchDB, Cloudant, Couchbase, MongoDB, Jackrabbit, XML-Databases, ThruDB, CloudKit, Prsevere, Riak-Basho, Scalaris |
Wide Columnar Store | BigTable, HBase, Apache Cassandra, Hypertable, KAI, OpenNeptune, Qbase, KDI |
Classification based on feature
Ben Scofield categorized NoSQL databases based on nonfunctional categories (“(il)ities“) plus a rating of their feature coverage: [citation needed]
Data Model | Performance | Scalability | Flexibility | Complexity | Functionality |
---|---|---|---|---|---|
Key–value Stores | high | high | high | none | variable (none) |
Column Store | high | high | moderate | low | minimal |
Document Store | high | variable (high) | high | low | variable (low) |
Graph Database | variable | variable | high | high | graph theory |
Relational Database | variable | variable | low | moderate | relational algebra. |
It has been suggested that this article be merged into Comparison of structured storage software. (Discuss) Proposed since March 2011. |
Examples
Document store
The central concept of a document store is the notion of a "document". While each document-oriented database implementation differs on the details of this definition, in general, they all assume that documents encapsulate and encode data (or information) in some standard formats or encodings. Encodings in use include XML, YAML, and JSON as well as binary forms like BSON, PDF and Microsoft Office documents (MS Word, Excel, and so on).
Different implementations offer different ways of organizing and/or grouping documents:
- Collections
- Tags
- Non-visible Metadata
- Directory hierarchies
Compared to relational databases, for example, collections could be considered as tables as well as documents could be considered as records. But they are different: every record in a table has the same sequence of fields, while documents in a collection may have fields that are completely different.
Documents are addressed in the database via a unique key that represents that document. One of the other defining characteristics of a document-oriented database is that, beyond the simple key-document (or key–value) lookup that you can use to retrieve a document, the database will offer an API or query language that will allow retrieval of documents based on their contents. Some NoSQL document stores offer an alternative way to retrieve information using MapReduce techniques, in CouchDB the usage of MapReduce is mandatory if you want to retrieve documents based on the contents, this is called "Views" and it's an indexed collection with the results of the MapReduce algorithms.
Name | Language | Notes |
---|---|---|
BaseX | Java, XQuery | XML database |
Cloudant | Erlang, Java, Scala, C | JSON store (online service) |
Clusterpoint | C++ | XML, geared for Full text search |
Couchbase Server | Erlang, C, C++ | Support for JSON and binary documents |
Apache CouchDB | Erlang | JSON database |
djondb[6][7][8] | C++ | JSON, ACID Document Store |
ElasticSearch | Java | JSON, Search engine |
eXist | Java, XQuery | XML database |
Jackrabbit | Java | Java Content Repository implementation |
IBM Lotus Notes and Lotus Domino | LotusScript, Java, IBM X Pages, others | MultiValue |
MarkLogic Server | XQuery, Java, REST | XML database with support for JSON, text, and binaries |
MongoDB | C++, C#, Go | BSON store (binary format JSON) |
Oracle NoSQL Database | Java, C | |
OrientDB | Java | JSON, SQL support |
CoreFoundation Property list | C, C++, Objective-C | JSON, XML, binary |
Sedna | XQuery, C++ | XML database |
SimpleDB | Erlang | online service |
TokuMX | C++, C#, Go | MongoDB with Fractal Tree indexing |
OpenLink Virtuoso | C++, C#, Java, SPARQL | middleware and database engine hybrid |
Graph
This kind of database is designed for data whose relations are well represented as a graph (elements interconnected with an undetermined number of relations between them). The kind of data could be social relations, public transport links, road maps or network topologies, for example.
Name | Language | Notes |
---|---|---|
AllegroGraph | SPARQL | RDF GraphStore |
IBM DB2 | SPARQL | RDF GraphStore added in DB2 10 |
DEX | Java, C++, .NET | High-performance graph database |
FlockDB | Scala | |
InfiniteGraph | Java | High-performance, scalable, distributed graph database |
Neo4j | Java | |
OpenLink Virtuoso | C++, C#, Java, SPARQL | middleware and database engine hybrid |
OrientDB | Java | |
Sones GraphDB | C# | |
Sqrrl Enterprise | Java | Distributed, real-time graph database featuring cell-level security |
OWLIM | Java, SPARQL 1.1 | RDF graph store with reasoning |
VelocityGraph | C# | Fully Tinkerpop Blueprints compliant. Scalable hybrid object database and graph database |
Key–value stores
Key–value stores allow the application to store its data in a schema-less way. The data could be stored in a datatype of a programming language or an object. Because of this, there is no need for a fixed data model.[9][10] The following types exist:
KV - eventually consistent
KV - hierarchical
KV - cache in RAM
KV - solid state or rotating disk
- Aerospike
- BigTable
- CDB
- Couchbase Server
- Keyspace
- LevelDB
- MemcacheDB (using Berkeley DB)
- MongoDB
- OpenLink Virtuoso
- Tarantool
- Tokyo Cabinet
- Tuple space
- Oracle NoSQL Database
KV - ordered
Object database
- db4o
- GemStone/S
- InterSystems Caché
- JADE
- NeoDatis ODB
- ObjectDB
- Objectivity/DB
- ObjectStore
- ODABA
- OpenLink Virtuoso
- Versant Object Database
- WakandaDB
- ZODB
Tabular
Tuple store
Triple/Quad Store (RDF) database
Hosted
- Freebase
- OpenLink Virtuoso
- Datastore on Google Appengine
- Amazon DynamoDB
- Cloudant Data Layer (CouchDB)
Multivalue databases
- Northgate Information Solutions Reality, the original Pick/MV Database
- Extensible Storage Engine (ESE/NT)
- OpenQM
- Revelation Software's OpenInsight
- Rocket U2
- D3 Pick database
- InterSystems Caché
- InfinityDB
Cell database
- [1] Boardwalk
See also
- CAP theorem
- Comparison of object database management systems
- Comparison of structured storage software
- Faceted search
- Triplestore
- Distributed cache
References
- ^ a b Lith, Adam (2010). "Investigating storage solutions for large data: A comparison of well performing and scalable data storage solutions for real time extraction and batch insertion of data" (PDF). Göteborg: Department of Computer Science and Engineering, Chalmers University of Technology. p. 70. Retrieved 12 May 2011.
Carlo Strozzi first used the term NoSQL in 1998 as a name for his open source relational database that did not offer a SQL interface[...]
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- ^ "NoSQL 2009". Blog.sym-link.com. 12 May 2009. Retrieved 29 March 2010.
- ^ Mike Chapple. "The ACID Model".
- ^ A Yes for a NoSQL Taxonomy. High Scalability (2009-11-05). Retrieved on 2013-09-18.
- ^ The enterprise class NoSQL database. djondb. Retrieved on 2013-09-18.
- ^ http://tinman.cs.gsu.edu/~raj/8711/sp13/djondb/Report.pdf
- ^ Undefined Blog: Meeting with DjonDB. Undefvoid.blogspot.com. Retrieved on 2013-09-18.
- ^ Sandy (14 January 2011). "Key Value stores and the NoSQL movement". http://dba.stackexchange.com/questions/607/what-is-a-key-value-store-database: Stackexchange. Retrieved 1 January 2012.
Key–value stores allow the application developer to store schema-less data. This data usually consists of a string that represents the key, and the actual data that is considered to be the value in the "key–value" relationship. The data itself is usually some kind of primitive of the programming language (a string, an integer, or an array) or an object that is being marshaled by the programming language's bindings to the key–value store. This structure replaces the need for a fixed data model and allows proper formatting.
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- ^ Marc Seeger (21 September 2009). "Key-Value Stores: a practical overview" (PDF). http://blog.marc-seeger.de/2009/09/21/key-value-stores-a-practical-overview/: Marc Seeger. Retrieved 1 January 2012.
Key–value stores provide a high-performance alternative to relational database systems with respect to storing and accessing data. This paper provides a short overview of some of the currently available key–value stores and their interface to the Ruby programming language.
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- ^ "Riak: An Open Source Scalable Data Store". 28 November 2010. Retrieved 28 November 2010.
- ^ Tweed, Rob (2010). "A Universal NoSQL Engine, Using a Tried and Tested Technology" (PDF). p. 25.
Without exception, the most successful and well-known of the NoSQL databases have been developed from scratch, all within just the last few years. Strangely, it seems that nobody looked around to see whether there were any existing, successfully implemented database technologies that could have provided a sound foundation for meeting Web-scale demands. Had they done so, they might have discovered two products, GT.M and Caché.....*
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Further reading
- Pramod Sadalage and Martin Fowler (2012). NoSQL Distilled: A Brief Guide to the Emerging World of Polyglot Persistence. Addison-Wesley. ISBN 0-321-82662-0.
- Christof Strauch (2012). "NoSQL Databases" (PDF).
- Moniruzzaman AB, Hossain SA (2013). "NoSQL Database: New Era of Databases for Big data Analytics - Classification, Characteristics and Comparison".
- Kai Orend (2013). "Analysis and Classification of NoSQL Databases and Evaluation of their Ability to Replace an Object-relational Persistence Layer".
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(help) - Ganesh Krishnan, Sarang Kulkarni, Dharmesh Kirit Dadbhawala. "Method and system for versioned sharing, consolidating and reporting information".
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External links
- Christoph Strauch. "NoSQL whitepaper" (PDF). Hochschule der Medien, Stuttgart.
- Stefan Edlich. "NoSQL database List".
- Peter Neubauer (2010). "Graph Databases, NOSQL and Neo4j".
- Sergey Bushik (2012). "A vendor-independent comparison of NoSQL databases: Cassandra, HBase, MongoDB, Riak". NetworkWorld.