ArangoDB

ArangoDB is a free and open-source native multi-model database system^[1] developed by ArangoDB GmbH. The database system supports three data models (key/value, documents, graphs) with one database core and a unified query language AQL (ArangoDB Query Language). The query language is declarative and allows the combination of different data access patterns in a single query. ArangoDB is a NoSQL database system but AQL is similar in many ways to SQL.

ArangoDB has been referred to as a universal database^[2] but its creators refer to it as a "native multi-model"^[3] database to indicate that it was designed specifically to allow key/value, document, and graph data to be stored together and queried with a common language.^[4]

History[]

Started in 2011, the database was originally released under the name AvocadoDB, but changed to ArangoDB in 2012.^[5] The word "arango" refers to a little-known avocado variety.^[6]

Features[]

ArangoDB provides scalable queries when working with graph data.^{[7][page needed]} The database uses JSON as a default storage format,^[8] but internally it uses ArangoDB's VelocyPack – a fast and compact binary format for serialization and storage.^[9] ArangoDB can natively store a nested JSON object as a data entry inside a collection. Therefore, there is no need to disassemble the resulting JSON objects. Thus, the stored data would simply inherit the tree structure of the JSON data. ^[10]

ArangoDB works in a distributed cluster and is the first DBMS being certified for the Datacenter Operating System (DC/OS).^{[11][better source needed]} DC/OS allows the user to deploy ArangoDB on most existing ecosystems: Amazon Web Services (AWS), Google Compute Engine and Microsoft Azure. Moreover, it provides single-click deployment for the user's cluster.^[12]

ArangoDB provides integration with native JavaScript microservices directly on top of the DBMS using the Foxx framework,^[10] which is analogous to multithreaded Node.js.^[13]

The database has its own AQL (ArangoDB Query Language) and also provides GraphQL to write flexible native web services directly on top of the DBMS.^[14]

ArangoSearch is a new search engine feature in the 3.4 release. The search engine combines boolean retrieval capabilities with generalized ranking components allowing for data retrieval based on a precise vector space model. ^[15]

Query language[]

AQL (ArangoDB Query Language) is the SQL-like query language^[16] used in ArangoDB. It supports CRUD operations for both documents (nodes) and edges, but it is not a data definition language (DDL). AQL does support geospatial queries.

AQL is JSON-oriented as illustrated by the following query, which also illustrates the intuitive "dot" notation for accessing the values of keys:

 FOR x IN [{"a": {"A": 1}}, {"a": {"A": 2}}]
     FILTER x.a.A < 2
     RETURN x.a

Example[]

The following is a parameterized query for finding the number of descendants of a particular node (@start) in a graph named @g with @max nodes:

 FOR v IN 1 .. @max OUTBOUND @start GRAPH @g
     OPTIONS {uniqueVertices: "global", bfs: true }
 COLLECT WITH COUNT INTO c
 RETURN c

The uppercase words are AQL keywords. Notice how AQL is graph-aware. The OPTIONS are necessary to ensure the query can be run on a graph with cycles; "bfs" stands for breadth-first search.

Editions[]

ArangoDB Community Edition is a free native multi-model database written in C++ and available under an open-source license (Apache 2).

In addition to the Community Edition, ArangoDB Enterprise is a paid subscription that includes SmartGraphs, Satellite Collections and many enterprise-level security features.^[17]

See also[]

• Comparison of multi-model databases

References[]