dbpedia vs freebase

For my thesis project, i need a programmatically easy-to-use, powerful dictionary.. Therefore, i made (collected actually) a list of items that compares Freebase (http://www.freebase.com/) and Dbpedia (http://dbpedia.org/About).

• Dbpedia in general is more accurate as it directly rips off stuff from Wikipedia.  Freebase has a longer tail, since it collects info not just from Wikipedia, but also various other data sources.
• Both extract structured data from Wikipedia and make it available as RDF.
• Different schemas, identifiers, goals 
• Dbpedia -> stores its data as RDF tuples
• Freebase -> n-tuples
• Dbpedia -> data is automatically generated from Wikipedia several times a year
• Freebase -> data is automatically imported into Freebase after two weeks
• Dbpedia -> query via a SPARQL endpoint
• Freebase -> query via an MQL (Metaweb Query Language) API 
• Differences in
• Range of data sources
• Dbpedia -> focuses on just Wikipedia data
• Freebase -> import data from a wide variety of sources
• Ability to edit content
• Dbpedia -> requires that you edit Wikipedia for the change to appear in Dbpedia
• Freebase -> user-editable, contributions can be made via a public interface
• Structure of organizations
• Dbpedia -> funded by various organizations
• Freebase -> funded by Google

Through the common link of Wikipedia, it is possible to link some Freebase topics to Dbpedia resources.

(in Freebase RDF output OWL:SameAs points to Dbpedia) Example: http://dbpedia.org/page/Tetris

Freebase -> open, Creative Commons licenced, graph database

An entity is a single person, place or thing. Freebase connects entities together as a graph. 

Freebase API:

• a collection of HTTP API's providing read & write access to data stored in Freebase.
• different API's support different use cases.
• SEARCH API -> returns Freebase data given a free text user query.
• MQL Services (mqlread & mqlwrite) allow performing structured queries on Freebase using MQL. (This is the most common way to access graph data and to ask questions)
• TEXT Service -> takes an ID of a topic, returns its description
• IMAGE Service -> takes an ID, returns an image
• need to obtain an API Key - unique key generated using the console (on Google account, API console, create project)
• The project passes key (key=(API_KEY))
• Limit -> read quota of 100k per day, write 10k.
• for higer quota, do request more on google
• quotas on sandbox are more, but sandbox is erased every sunday!
• data dumps may be used locally for more limit (the size is 14 GB as i remember)
• depends on Google API client libraries

API Services:

• Search -> find entities by keyword search
• MQL Read -> retrieve detailed structured data about entities or collections of entities
• Topic API -> get a summary of all the info for an entity
• RDF API ->  get a summary of all the info for an entity in RDF
• Text Service -> get short textual descriptions for entities
• Image Service -> get repr. thumbnails for entities
• Freebase Suggest -> UI Widget picking entities

URI pattern for an API call:

GET https://www.googleapis.com/freebase/<version>/<apiname>[<path>]? [<urlparams>]

if request query is too long, params should be passed via POST.

but X-HTTP-Method-Override: GET header must be added to request.

version is v1 for production, v1sandbox for sandbox environment (experimental)

callback -> url param will return a json structure enclosed in a javascript function call as an argument to the function (supports JSONP pattern)

Freebase API Sample Code Generator (http://codify.freebaseapps.com/) -> strongly recommend to try this!