All of the data is stored in MongoDB 11, a schema-less, document-oriented database. MongoDB stores JSON-style documents which are basically collections of key-value pairs. This unconventional choice was driven by several key advantages provided by MongoDB compared to SQL and objectoriented alternatives. MongoDB is schema free and does not impose any constraints on the structure of the documents it stores. This makes it particularly well-suited for storing schema.org types because they rely heavily on multiple inheritence, an intrinsic property that is hard to map to relational databases. By defining the data schema only in the application logic, we are still able to ensure data integrity when it is needed, while allowing the use of unstructured fields within our schemas as well. This technique also facilitates frequent schema modifications, such as the addition of new semantic types, because changes can be made in the code without requiring any updates to the database.