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Freebase was a large collaborative knowledge base consisting of data composed mainly by its community members. It was an online collection of structured data harvested from many sources, including individual, user-submitted wiki contributions.〔 〕 Freebase aimed to create a global resource that allowed people (and machines) to access common information more effectively. It was developed by the American software company Metaweb and ran publicly since March 2007. Metaweb was acquired by Google in a private sale announced 16 July 2010. Google's Knowledge Graph was powered in part by Freebase. Freebase data was available for commercial and non-commercial use under a Creative Commons Attribution License, and an open API, RDF endpoint, and a database dump was provided for programmers. On 16 December 2014, Knowledge Graph announced that it would shut down Freebase over the succeeding six months and help with the move of the data from Freebase to Wikidata. == Overview == On 3 March 2007 Metaweb announced Freebase, describing it as "an open shared database of the world's knowledge", and "a massive, collaboratively edited database of cross-linked data". Often understood as a database model using Wikipedia-turned-database or entity-relationship model, Freebase provided an interface that allowed non-programmers to fill in structured data, or metadata, of general information and to categorize or connect data items in meaningful, semantic ways. Described by Tim O'Reilly upon the launch, "Freebase is the bridge between the bottom up vision of Web 2.0 collective intelligence and the more structured world of the semantic web".〔 Freebase contained data harvested from sources such as Wikipedia, NNDB, Fashion Model Directory and MusicBrainz, as well as data contributed by its users. The structured data was licensed under the Creative Commons Attribution License, and a JSON-based HTTP API was provided to programmers for developing applications on any platform to utilize the Freebase data. The source code for the Metaweb application itself was proprietary. Freebase ran on a database infrastructure created in-house by Metaweb that used a graph model: Instead of using tables and keys to define data structures, Freebase defined its data structure as a set of nodes and a set of links that established relationships between the nodes. Because its data structure was non-hierarchical, Freebase could model much more complex relationships between individual elements than a conventional database, and it was open for users to enter new objects and relationships into the underlying graph. Queries to the database were made in Metaweb Query Language (MQL) and served by a triplestore called graphd. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Freebase」の詳細全文を読む スポンサード リンク
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