NoSQL
NoSQL (تختصر عادة إلى Not Only SQL[1][2][unreliable source?])، هي قاعدة بيانات توفر آلية لتخزين واسترجاع البيانات that is modeled in means other than the tabular relations المستخدمة في قواعد البيانات العلائقية. Motivations for this approach include simplicity of design, horizontal scaling and finer control over availability. The data structures used by NoSQL databases (e.g. key-value, graph, or document) differ from those used in relational databases, making some operations faster in NoSQL and some faster in relational databases. The particular suitability of a given NoSQL database depends on the problem it must solve.
قواعد بيانات NoSQL تستخدم بشكل متزايد في البيانات الضخمة وتطبيقات real-time web.[3] يطلق على أنظمة NoSQL أيضاً "Not only SQL" للتأكيد على أنها يمكنها أيضاً أن تعدم لغات الاستعلام الشبيهة بSQL-. Many NoSQL stores compromise consistency (in the sense of the CAP theorem) in favor of availability and partition tolerance. Barriers to the greater adoption of NoSQL stores include the use of low-level query languages, the lack of standardized interfaces, and huge investments in existing SQL.[4] Most NoSQL stores lack true ACID transactions, although a few recent systems, such as FairCom c-treeACE, Google Spanner (though technically a NewSQL database) and FoundationDB, have made them central to their designs.
معوقات الاعتماد
Barriers to wider NoSQL adoption include their use of low-level query languages instead of SQL, inability to perform ad hoc joins across tables, lack of standardized interfaces, and significant investments already made in relational databases.[5] Some NoSQL systems risk losing data through lost writes or other forms, though features like write-ahead logging—a method to record changes before they’re applied—can help prevent this.[6][7] For distributed transaction processing across multiple databases, keeping data consistent is a challenge for both NoSQL and relational systems, as relational databases cannot enforce rules linking separate databases, and few systems support both ACID transactions and X/Open XA standards for managing distributed updates.[8][9] Limitations within the interface environment are overcome using semantic virtualization protocols, such that NoSQL services are accessible to most operating systems.[10]
التاريخ
The term NoSQL was used by Carlo Strozzi in 1998 to name his lightweight Strozzi NoSQL open-source relational database that did not expose the standard Structured Query Language (SQL) interface, but was still relational.[11] His NoSQL RDBMS is distinct from the around-2009 general concept of NoSQL databases. Strozzi suggests that, because the current NoSQL movement "departs from the relational model altogether, it should therefore have been called more appropriately 'NoREL'",[12] referring to "not relational".
Johan Oskarsson, then a developer at Last.fm, reintroduced the term NoSQL in early 2009 when he organized an event to discuss "open-source distributed, non-relational databases".[13] The name attempted to label the emergence of an increasing number of non-relational, distributed data stores, including open source clones of Google's Bigtable/MapReduce and Amazon's DynamoDB.
أنواع وأمثلة
There are various ways to classify NoSQL databases, with different categories and subcategories, some of which overlap. What follows is a non-exhaustive classification by data model, with examples:[14]
Key–value store
Key–value (KV) stores use the associative array (also called a map or dictionary) as their fundamental data model. In this model, data is represented as a collection of key–value pairs, such that each possible key appears at most once in the collection.[17][18]
The key–value model is one of the simplest non-trivial data models, and richer data models are often implemented as an extension of it. The key–value model can be extended to a discretely ordered model that maintains keys in lexicographic order. This extension is computationally powerful, in that it can efficiently retrieve selective key ranges.[19]
Key–value stores can use consistency models ranging from eventual consistency to serializability. Some databases support ordering of keys. There are various hardware implementations, and some users store data in memory (RAM), while others on solid-state drives (SSD) or rotating disks (aka hard disk drive (HDD)).
Document store
The central concept of a document store is that of a "document". While the details of this definition differ among document-oriented databases, 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 and binary forms like BSON. Documents are addressed in the database via a unique key that represents that document. Another defining characteristic of a document-oriented database is an API or query language to retrieve documents based on their contents.
Different implementations offer different ways of organizing and/or grouping documents:
- Collections
- Tags
- Non-visible metadata
- Directory hierarchies
Compared to relational databases, collections could be considered analogous to tables and documents analogous to 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.
Graph
Graph databases are designed for data whose relations are well represented as a graph consisting of elements connected by a finite number of relations. Examples of data include social relations, public transport links, road maps, network topologies, etc.
- Graph databases and their query language
تطبيقات قواعد بيانات NoSQL
- Column: Accumulo, Cassandra, Druid, HBase, Vertica
- Document: Clusterpoint, Apache CouchDB, Couchbase, MarkLogic, MongoDB
- Key-value: Dynamo, FoundationDB, MemcacheDB, Redis, Riak, FairCom c-treeACE, Aerospike
- Graph: Allegro, Neo4J, InfiniteGraph, OrientDB, Virtuoso, Stardog
- Multimodel Databases: ArangoDB, Alchemy Database, CortexDB
المصطلح | قاعدة البيانات المطابقة |
---|---|
Key-Value Cache | Coherence, eXtreme Scale, GigaSpaces, GemFire, Hazelcast, Infinispan, JBoss Cache, Memcached, Repcached, Terracotta, Velocity |
Key-Value Store | Flare, Keyspace, RAMCloud, SchemaFree, Hyperdex |
Key-Value Store (Eventually-Consistent) | DovetailDB, Dynamo, Riak, Dynomite, MotionDb, Voldemort, SubRecord |
Key-Value Store (Ordered) | Actord, FoundationDB, Lightcloud, Luxio, MemcacheDB, NMDB, Scalaris, TokyoTyrant |
Data-Structures server | Redis |
Tuple Store | Apache River, Coord, GigaSpaces |
Object Database | DB4O, Perst, Shoal, ZopeDB, |
Document Store | Clusterpoint, Couchbase, CouchDB, MarkLogic, MongoDB, XML-databases |
Wide Columnar Store | BigTable, Cassandra, Druid, HBase, Hypertable, KAI, KDI, OpenNeptune, Qbase |
الآداء
نموذج البيانات | الآداء | التدرجية | المرونة | التعقيد | التشغيل |
---|---|---|---|---|---|
Key–Value Store | مرتفع | مرتفع | مرتفع | لا يوجد | متغير (لا يوجد) |
Column-Oriented Store | مرتفع | مرتفع | متوسط | منخفض | اسمي |
Document-Oriented Store | مرتفع | متغير (مرتفع) | مرتفع | منخفض | متغير (منخفض) |
قاعدة بيانات المخططات | متغير | متغير | مرتفع | مرتفع | نظرية المخططات |
قاعدة البيانات العلائقية | متغير | متغير | منخفض | متوسط | الجبر العلائقي |
معالجة البيانات العلائقية
Since most NoSQL databases lack ability for joins in queries, the database schema generally needs to be designed differently. There are three main techniques for handling relational data in a NoSQL database. (See table join and ACID support for NoSQL databases that support joins.)
الاستعلامات المتعددة
Instead of retrieving all the data with one query, it is common to do several queries to get the desired data. NoSQL queries are often faster than traditional SQL queries, so the cost of additional queries may be acceptable. If an excessive number of queries would be necessary, one of the other two approaches is more appropriate.
Caching/Replication/Non-normalized Data
Instead of only storing foreign keys, it is common to store actual foreign values along with the model's data. For example, each blog comment might include the username in addition to a user id, thus providing easy access to the username without requiring another lookup. When a username changes, however, this will now need to be changed in many places in the database. Thus this approach works better when reads are much more common than writes.[21]
Nesting data
With document databases like MongoDB it is common to put more data in a smaller number of collections. For example, in a blogging application, one might choose to store comments within the blog post document, so that with a single retrieval one gets all the comments. Thus in this approach a single document contains all the data needed for a specific task.
ACID and join support
A database is marked as supporting ACID properties (atomicity, consistency, isolation, durability) or join operations if the documentation for the database makes that claim. However, this doesn't necessarily mean that the capability is fully supported in a manner similar to most SQL databases.
Database | ACID | Joins |
---|---|---|
Aerospike | نعم | لا |
AgensGraph | نعم | نعم |
Apache Ignite | نعم | نعم |
ArangoDB | نعم | نعم |
Amazon DynamoDB | نعم | لا |
Couchbase | نعم | نعم |
CouchDB | نعم | نعم |
IBM Db2 | نعم | نعم |
InfinityDB | نعم | لا |
LMDB | نعم | لا |
MarkLogic | نعم | نعم[nb 1] |
MongoDB | نعم | نعم[nb 2] |
OrientDB | نعم | نعم[nb 3] |
أمثلة
تخزين الوثائق
المخططات
الاسم | اللغة | هوامش |
---|---|---|
AllegroGraph | SPARQL | RDF GraphStore |
DEX/Sparksee | C++, Java, .NET, Python | High-performance graph database |
FlockDB | Scala | |
IBM DB2 | SPARQL | RDF GraphStore added in DB2 10 |
InfiniteGraph | Java | High-performance, scalable, distributed graph database |
Neo4j | Java | |
OWLIM | Java, SPARQL 1.1 | RDF graph store with reasoning |
OrientDB | Java | |
Sones GraphDB | C# | |
Sqrrl Enterprise | Java | Distributed, real-time graph database featuring cell-level security |
OpenLink Virtuoso | C++, C#, Java, SPARQL | middleware and database engine hybrid |
Stardog | Java, SPARQL | semantic graph database |
Key-value stores
KV - eventually consistent
KV - ordered
- Berkeley DB
- FairCom c-treeACE/c-treeRTG
- FoundationDB
- IBM Informix C-ISAM
- InfinityDB
- LMDB
- MemcacheDB
- NDBM
KV - RAM
KV - solid-state drive or rotating disk
- Aerospike
- BigTable
- CDB
- Clusterpoint XML database
- Coherence
- Couchbase Server
- FairCom c-treeACE
- GT.M[26]
- Hibari
- Keyspace
- LevelDB
- LMDB
- MemcacheDB (using Berkeley DB)
- MongoDB
- OpenLink Virtuoso
- Oracle NoSQL Database
- Tarantool
- Tokyo Cabinet
- Tuple space
Object database
- db4o
- GemStone/S
- InterSystems Caché
- JADE
- NeoDatis ODB
- ObjectDatabase++
- ObjectDB
- Objectivity/DB
- ObjectStore
- ODABA
- Perst
- OpenLink Virtuoso
- Versant Object Database
- ZODB
Tabular
Tuple store
- Apache River
- GigaSpaces
- Tarantool
- TIBCO ActiveSpaces
- OpenLink Virtuoso
Triple/quad store (RDF) database
- Apache JENA
- MarkLogic
- Ontotext-OWLIM
- Oracle NoSQL database
- SparkleDB
- Virtuoso Universal Server
- Stardog
Hosted
- Amazon DynamoDB
- Cloudant Data Layer (CouchDB)
- Datastore on Google Appengine
- Freebase
- OpenLink Virtuoso
Multivalue databases
- D3 Pick database
- Extensible Storage Engine (ESE/NT)
- InfinityDB
- InterSystems Caché
- Northgate Information Solutions Reality, the original Pick/MV Database
- OpenQM
- Revelation Software's OpenInsight
- Rocket U2
قاعدة البيانات متعددة النماذج
قاعدة البيانات التصحيحية
قاعدة البيانات الخلوية
انظر أيضاً
- CAP theorem
- Comparison of object database management systems
- Comparison of structured storage software
- Faceted search
- Triplestore
- Distributed cache
- Correlation database
- MultiValue database
المصادر
- ^ "NoSQL (Not Only SQL)".
NoSQL database, also called Not Only SQL
- ^ Martin Fowler. "NosqlDefinition".
many advocates of NoSQL say that it does not mean a "no" to SQL, rather it means Not Only SQL
- ^ "RDBMS dominate the database market, but NoSQL systems are catching up". DB-Engines.com. 21 Nov 2013. Retrieved 24 Nov 2013.
- ^ K. Grolinger, W.A. Higashino, A. Tiwari, M.A.M. Capretz (2013). "Data management in cloud environments: NoSQL and NewSQL data stores" (PDF). JoCCASA, Springer. Retrieved 8 Jan 2014.
{{cite web}}
: CS1 maint: multiple names: authors list (link) - ^ Grolinger, K.; Higashino, W. A.; Tiwari, A.; Capretz, M. A. M. (2013). "Data management in cloud environments: NoSQL and NewSQL data stores" (PDF). Aira, Springer. Retrieved 8 January 2014.
- ^ "Large volume data analysis on the Typesafe Reactive Platform". Slideshare.net. 11 June 2015. Retrieved 2017-03-06.
- ^ Fowler, Adam. "10 NoSQL Misconceptions". Dummies.com. Retrieved 2017-03-06.
- ^ "No! to SQL and No! to NoSQL". Iggyfernandez.wordpress.com. 29 July 2013. Retrieved 2017-03-06.
- ^ Chapple, Mike. "The ACID Model". about.com. Archived from the original on 29 December 2016. Retrieved 26 September 2012.
- ^ Lawrence, Integration and virtualization of relational SQL and NoSQL systems including MySQL and MongoDB (2014). "Integration and virtualization of relational SQL and NoSQL systems including MySQL and MongoDB". International Conference on Computational Science and Computational Intelligence 1.
- ^ Lith, Adam; Mattson, Jakob (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[...]
- ^ "NoSQL Relational Database Management System: Home Page". Strozzi.it. 2 October 2007. Retrieved 29 March 2010.
- ^ "NoSQL 2009". Blog.sym-link.com. 12 May 2009. Archived from the original on 16 July 2011. Retrieved 29 March 2010.
- ^ Strauch, Christof. "NoSQL Databases" (PDF). pp. 23–24. Retrieved 2017-08-27.
- ^ https://apacheignite.readme.io/docs Ignite Documentation
- ^ https://www.infoworld.com/article/3135070/data-center/fire-up-big-data-processing-with-apache-ignite.html fire-up-big-data-processing-with-apache-ignite
- ^ Sandy (14 January 2011). "Key Value stores and the NoSQL movement". 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 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.
- ^ Seeger, Marc (21 September 2009). "Key-Value Stores: a practical overview" (PDF). 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.
- ^ Katsov, Ilya (1 March 2012). "NoSQL Data Modeling Techniques". Ilya Katsov. Retrieved 8 May 2014.
- ^ "TerminusDB an open-source in-memory document graph database". terminusdb.com. Retrieved 2021-12-16.
- ^ "Moving From Relational to NoSQL: How to Get Started". Couchbase.com. Retrieved 11 November 2019.
- ^ "Can't do joins with MarkLogic? It's just a matter of Semantics! - General Networks". Gennet.com. Archived from the original on 3 March 2017. Retrieved 2017-03-06.
- ^ "Sharded Collection Restrictions". docs.mongodb.com. Retrieved 2020-01-24.
- ^ "SQL Reference · OrientDB Manual". OrientDB.com. Retrieved 2020-01-24.
- ^ "Riak: An Open Source Scalable Data Store". 28 November 2010. Retrieved 28 November 2010 * OpenLink Virtuoso
- Project Voldemort.
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- Project Voldemort.
- ^ Tweed, Rob; George James (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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قراءات إضافية
- 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.
- Dan McCreary & Ann Kelly (2013). Making Sense of NoSQL: A guide for managers and the rest of us. ISBN 9781617291074.
- 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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: CS1 maint: multiple names: authors list (link) - Sugam Sharma. "A Brief Review on Modern NoSQL Data Models, Handling Big Data".
وصلات خارجية
- Strauch, Christof. "NoSQL whitepaper" (PDF). Stuttgart: Hochschule der Medien.
- Edlich, Stefan. "NoSQL database List".
- Neubauer, Peter (2010). "Graph Databases, NOSQL and Neo4j".
- Bushik, Sergey (2012). "A vendor-independent comparison of NoSQL databases: Cassandra, HBase, MongoDB, Riak". NetworkWorld.
- Zicari, Roberto V. (2014). "NoSQL Data Stores – Articles, Papers, Presentations". odbms.org.