Wikidata aims to create a free knowledge base about the world that can be read and edited by humans and machines alike. It will provide data in all the languages of the Wikimedia projects, and allow for the central access to data in a similar vein as Wikimedia Commons does for multimedia files. Wikidata is proposed as a new Wikimedia hosted and maintained project.

Apache Accumulo is a sorted, distributed key/value store based on Google's BigTable design. It is built on top of Apache Hadoop, Zookeeper, and Thrift. It features a few novel improvements on the BigTable design in the form of cell-level access labels and a server-side programming mechanism that can modify key/value pairs at various points in the data management process.

Here is a (naturally incomplete) list of so called NoSQL datastores that are available ‘in the cloud’.

This module implements the hstore data type for storing sets of key/value pairs within a single PostgreSQL value. This can be useful in various scenarios, such as rows with many attributes that are rarely examined, or semi-structured data. Keys and values are simply text strings.

Processing large volumes of Linked Data requires sophisticated methods and tools. In the recent years we have mainly focused on systems based on relational databases and bespoke systems for Linked Data processing. Cloud computing offerings such as SimpleDB or BigQuery, and cloud-enabled NoSQL systems including Cassandra or CouchDB as well as frameworks such as Hadoop offer appealing alternatives along with great promises concerning performance, scalability and elasticity. In this paper we state a number of Linked Dataspecific requirements and review existing cloud computing offerings as well as NoSQL systems that may be used in a cloud computing setup, in terms of their applicability and usefulness for processing datasets on a large-scale.

Iris Couch provides easy hosted CouchDB.

Web Data Commons will extract all Microformat, Microdata and RDFa data that is contained in the Common Crawl corpus and will provide the extracted data for free download in the form of RDF-quads as well as CSV-tables for common entity types (e.g. product, organization, location, ...).

Lessons from database research have been applied in academic fields ranging from bioinformatics to next-generation Internet architecture and in industrial uses including Web-based e-commerce and search engines. The core ideas in the field have become increasingly influential. This text provides both students and professionals with a grounding in database research and a technical context for understanding recent innovations in the field. The readings included treat the most important issues in the database area -- the basic material for any DBMS professional.This fourth edition has been substantially updated and revised, with 21 of the 48 papers new to the edition, four of them published for the first time. Many of the sections have been newly organized, and each section includes a new or substantially revised introduction that discusses the context, motivation, and controversies in a particular area, placing it in the broader perspective of database research. Two introductory articles, never before published, provide an organized, current introduction to basic knowledge of the field; one discusses the history of data models and query languages and the other offers an architectural overview of a database system. The remaining articles range from the classical literature on database research to treatments of current hot topics, including a paper on search engine architecture and a paper on application servers, both written expressly for this edition. The result is a collection of papers that are seminal and also accessible to a reader who has a basic familiarity with database systems.

Bulbs is an open-source Python persistence framework for graph databases and the first piece of a larger Web-development toolkit that will be released in the upcoming weeks.

It’s like an ORM for graphs, but instead of SQL, you use the graph-traveral language Gremlin to query the database.

You can use it to connect to any Blueprints-enabled database, including TinkeGraph, Neo4j, OrientDB, Dex, and OpenRDF (and there is an InfiniteGraph implementation in development).

You can use Bulbs from within any Python Web-development framework, including Flask, Pyramid, and Django.

MADlib is an open-source library for scalable in-database analytics. It provides data-parallel implementations of mathematical, statistical and machine learning methods for structured and unstructured data.

This paper covers two topics: The first part discusses new methods in historical
research using semantic networking models. After a theoretical approach (graph
and network theory), general semantic networks are introduced. This leads to
the second topic, the semantic historical database, which can hold any historical
information and relate these to one another. Examples are given from a work-inprogress on merchant networks in Portuguese European–Asian trade. The paper
finishes by conveying some preliminary findings

Historical, semantic networks are a computer-based method for working with historical data. Objects (e.g., people, places, events) can be entered into a database and connected to each other relationally. Both qualitative and quantitative research could profit from such an approach. Moreover, data can easily be shared among researchers. histcross is a project in progress that implements historical semantic networks.

Historic Crossroads (histcross) is a semantic database designed for the research needs of historians. Essentially, it enables researchers to enter information into the database and link pieces of this information sematically to each other.

A set of hacks to setup a dbpedia endpoint through neo4j.

eRDF is a novel query engine developped at the Vrije Universiteit Amsterdam. It uses the robustness of evolutionary algorithms to answer complicated SPARQL query over many end points.

4store was designed by Steve Harris and developed at Garlik to underpin their Semantic Web applications. It has been providing the base platform for around 3 years. At times holding and running queries over databases of 15GT, supporting a Web application used by thousands of people.

Acoustid is an open source project that aims to create a free database of audio fingerprints with mapping to the MusicBrainz metadata database and provide a web service for audio file identification using this database.

This document describes the use of HTTP operations for the purpose of managing a collection of graphs in the REST architectural style.

A backend store for the Annotator using Flask and CouchDB.

The Virtuoso Redland RDF Provider is an implementation of the Storage API, Model and Query interfaces of the Redland framework for RDF. This provider enables the execution of queries via the Redland Rasqal query engine or via Virtuoso query engine directly against the Virtuoso OpenSource Quad Store.

This section will present basic graph traversals by way of examples on the simple property graph diagrammed below.

Gremlin is a domain specific programming language for graphs. Graphs are data structures where there exists vertices (i.e. dots, nodes) and edges (i.e. lines, arcs). Gremlin was designed to work with a type of graph called a property graph.

During the late 19th and early 20th centuries, thousands of African Americans were lynched in the southern region of the United States. Previous research on lynching has been based largely on existing inventories of the victims of this form of extralegal punishment. While extremely valuable, these inventories suffer from important limitations in how much they can tell us about those victims, about the local conditions that affected the risk of an individual becoming the victim of a lynch mob, or about how the relationship between individual characteristics and the likelihood of being lynched may have varied across time and place. We are creating a new source of data that will introduce the individual victim into research on lynching, and provide information about the social relations and environment within which each victim was embedded. Our procedure merges information from an inventory of nearly 2,800 individuals who were lynched between 1882 and 1930 (Beck and Tolnay 2005 – See Table 1) with: 1) the original enumerators’ manuscripts for the Census immediately preceding the lynching (e.g., the 1880 Census for an 1885 lynching); and 2) geocode information on the county of lynching and county of residence for identified victims. The main contribution of this work is twofold: we develop new spatially-oriented methods of matching individuals to their census records; and, we create an historical data source that will allow researchers studying lynching, hate crimes, and ethnic conflict to link information for individuals and households to characteristics of the local context within which the victim resided or was lynched.

The goal is to accumulate a database of lynchings that took place at any date within the present borders of the United States.  We hope to make the lynching database analogous to the comprehensive list of legal executions compiled by M. Watt Espy of the Capital Punishment Research Project, Headland, Alabama.  We will collect information for individual lynching incidents on an ongoing basis.  

Cradle is an asynchronous javascript client for CouchDB. It is somewhat higher-level than most other CouchDB clients, requiring a little less knowledge of CouchDB's REST API. Cradle also has built-in write-through caching, giving you an extra level of speed, and making document updates and deletion easier.

Three of CouchDB’s creators show you how to use this document-oriented database as a standalone application framework or with high-volume, distributed applications. With its simple model for storing, processing, and accessing data, CouchDB is ideal for web applications that handle huge amounts of loosely structured data.

BayesStore is a novel probabilistic data management architecture built on the principle of handling statistical models and probabilistic inference tools as first-class citizens of the database system. BayesStore represents model and evidence data as relational tables; implements inference algorithms efficiently in SQL; adds probabilistic relational operators to the query engine; optimizes queries with both relational and inference operators. The design goals of BayesStore are: (1) to be able to support efficient query processing over different models compared to the off-the-shelf machine learning libraries; (2) to be able to support extensible API for plugging in new models and inference algorithms; and (3) to be able to scale up to very large data sets.

PostgreSQL can be extended to support new data types. This section describes how to define new base types, which are data types defined below the level of the SQL language. Creating a new base type requires implementing functions to operate on the type in a low-level language, usually C.

MongoEngine is an Object-Document Mapper, written in Python for working with MongoDB.

MongoHQ is the hosted database solution for easily getting your apps up and running with MongoDB.

MongoDB supports two-dimensional geospatial indexes. It is designed with location-based queries in mind, such as "find me the closest N items to my location." It can also efficiently filter on additional criteria, such as "find me the closest N museums to my location."

It provides constructs that will seem familiar to those used to ORMs like SQLAlchemy or Django but which are backed by an RDF store containing multiple graphs and are ultimately expressed in OWL.

Creates a GraphViz dot file for the specified app names. You can pass multiple app names and they will all be combined into a single model. Output is usually directed to a dot file.

Turnguard's QuadStore is the first draft of an own implementation of a QuadStore with main focus on data-retrieval speed. Implements full-text search.

The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.

Here you can explore the geographical information provided by Yahoo in the GeoPlanet API and data set. Simply enter a location in the form and submit it to get detailed information about the place you are looking for - including its ancestors, siblings, children and other relationships.

This collection of photos is for anyone to use in just about any way they'd like. You may NOT, however, redistribute these photos individually or en masse, as photos, to any other websites or offline buyers. The photos themselves are still the intellectual property of their respective owners and you are merely receiving permission to use them in your designs, your art, your personal and professional projects, as your desktop backgrounds.

Taps is a temporary web service you run on a server that has access to the database you want to export. You can then run the client to connect to that service and pull data out of it in chunks. It works through firewalls, doesn’t require a direct ssh connection, and - best of all - it’s database independent.

"Rather than moving towards amalgamation and interoperability across databases, you really get the sense that everybody’s been busy grabbing at whatever piles of text they can lay their hands on, building the biggest little mudhill they can manage to put up, and then building walls around it. There are interstitial services that help a user 'jump' from one little fragmented collection to another and portals that aim to be a 'top level' to return to, sure, but we should be doing better by now."

One can now have RDF and full text indexing on the desktop without running a Java VM or any other memory-intensive software.

Redis is a key-value database. It is similar to memcached but the dataset is not volatile, and values can be strings, exactly like in memcached, but also lists and sets with atomic operations to push/pop elements.

This post is both a tutorial and a "getting started" overview. You will learn about Cassandra's features, data model, API, and operational requirements—everything you need to know to deploy a Cassandra-backed service.

This document describes SPARQL/Update, an update language for RDF graphs. It uses a syntax derived form SPARQL. Update operations are performed on a collection of graphs in a Graph Store. Operations are provided to change existing RDF graphs as well as create and remove graphs with the Graph Store.

Intute is a free online service providing you with a database of hand selected Web resources for education and research.

Assured Date-Period: 5/5/1,789 - 11/9/1,799

Geniusql is a public domain, low-level Object-Relational Mapper for Python applications. It primarily uses a generic Table Data Gateway architecture (as opposed to the more tightly-coupled Active Record architecture recently popularized by Ruby On Rails and Django).

These databases integrate information from various projects at the Library and Information Center at Dharma Drum Buddhist College. By providing information on Chinese calendar dates, as well as an onomasticon of person and place names from Buddhist sources they help with disambiguation and geo-spatial referencing of names and dates. The data is openly available through various web-services.

Perform full text searches, filtered by types that are inferred.

sqlparse is a non-validating SQL parser for Python. It provides support for parsing, splitting and formatting SQL statements.

OpenLink Software provides a backup up of the current DBpedia 3.2 Database as hosted on the live service at http://dbpedia.org/, that users can restore into a Virtuoso EC2 AMI instance in the cloud, providing them with an instance of DBpedia for their own use.

Open Anzo has an impressive list of features beyond the simple ability to load and query triples.

Intelligent schema migrations for Django apps.

"...even if web of data turns out to be all its proponents want it to be, narrative won’t still be part of it, but it will be something to put on top." Problematic assumption that facts precede narratives, that narratives are something you "put on top" of or weave out of facts or data... rather than facts being distilled from or abstracted out of narratives.

Anzo is an open source enterprise-featured RDF store and service oriented middleware platform that provides support for multiple users, distributed clients, offline work, real-time notification, named-graph modularization, versioning, access controls, and transactions with preconditions.

The Timeline Index : People, Periods, Places and Events in a chronological context.

voiD is a vocabulary and a set of instructions that enables the discovery and usage of linked datasets.

The App Engine datastore provides a query engine and transactional storing with a simple API, all running on Google's scalable infrastructure. The Python interface includes a data modelling API and a SQL-like query language called GQL, making developing scalable data-backed apps as easy as with simple web hosting.

ActiveRDF is a library for accessing RDF data from Ruby programs. It can be used as data layer in Ruby-on-Rails, similar to ActiveRecord (which provides an O/R mapping to relational databases).

To find out who was there with a given person, I had to first figure out the discrete ranges of the chosen person’s visits. This was not itself easy, because the data was often incomplete (sometimes missing a value for the day, sometimes for the month, sometimes for the year, etc.; sometimes there wouldn’t even be a departure date or arrival date). The dates were a nightmare to work with.

The Google Spreadsheets Data API allows client applications to view and update Spreadsheets content in the form of Google Data API feeds. Your client application can request a list of a user's spreadsheets, edit or delete content in an existing Spreadsheets worksheet, and query the content in an existing Spreadsheets worksheet.

The History Engine is an educational tool that gives students the opportunity to learn history by doing the work—researching, writing, and publishing—of a historian.

One of the advantages of how RDF works is that it is possible to query a dataset without knowing anything about the data set at the outset. There are some simple queries that you can get started with to show how this works.

An online relational database with biographical information about approximately 40,000 individuals as of July 2008. The data is meant to be useful for statistical and spatial analysis as well as serving as a kind of biographical reference.

Persevere is an open source set of tools for persistence and distributed computing using an intuitive standards-based JSON interfaces of HTTP REST, JSON-RPC, JSONPath, and HTTP Channels.

AtomServer is a generic data store implemented as a REST-ful web service. It is designed as a GData-style Atom Store.

A standalone search engine, meant to provide fast, size-efficient and relevant fulltext search functions to other applications. Sphinx was specially designed to integrate well with SQL databases and scripting languages.

pg/python is an open source project working toward the improvement of Python interfaces to PostgreSQL.

Prolog packages for reading, querying and storing semantic web documents as well as XPCE libraries that provide visualisation and editing.

The household returns and ancillary records for the censuses of Ireland of 1901 and 1911.

Your webserver can now serve a standard HTML form that will allow your users to upload their content directly into Amazon S3 on your behalf.

A fully searchable online edition of the largest body of texts detailing the lives of non-elite people ever published, containing accounts of over 100,000 criminal trials held at London's central criminal court.

An easy to use data access system was developed that meets UNSD’s vision of providing an integrated information resource with current, relevant and reliable statistics free of charge to the global community.

Conveyor can be used like an application-agnostic version of MySQL binlogs, which can be replayed to write data into multiple, diverse data stores.

Photos, films, virtual tours, historical articles and artifacts, and books and memoirs.

More than 7,000 items relating to Irish culture and heritage.

The wiki markup for each article is transformed into machine-readable XML, and common relational features such as templates, infoboxes, categories, article sections, and redirects are extracted in tabular form.

Jaql is a new query language being developed for JSON data.

CouchDB provides a bulk insert/update feature.

Views map keys to values, where the key is automatically indexed and can be used to filter and/or sort results. Keys can be any JSON object, which enables a whole class of tricks that are rather non-obvious…

Amazon SimpleDB is a web service for running queries on structured data in real time.