Fluree
Blockchain
Fluree is a ledger-backed semantic graph database with a cloud-native architecture.
Compression
Delta Encoding Null Suppression Prefix Compression
Each transaction to Fluree contains either a new RDF triple or an update to an RDF triple already in the db. Fluree converts all subject prefixes to an integer which is used in the hashing of the RDF triples. There are no null values stored in an RDF store due to the nature of the Subject-Predicate-Object format, so null values are suppressed by default.
Data Model
Relational Document / XML Graph Triplestore / RDF
Fluree is an extended-RDF graph database which emulates a document and relational database in that it can support GraphQL, SPARQL, document like JSON data, and a limited sub-set of SQL.
Indexes
AVL-Tree Inverted Index (Full Text)
Fluree indexes are built using an AVL-tree structure and an inverted index using Lucene is available as a configuration option on individual predicates. When "fullText": true is added to a predicate an additional index is created and managed by Fluree, specifically for the predicates where this option is enabled.
Query Interface
Custom API SQL GraphQL SPARQL HTTP / REST
In addition to supporting GraphQL and SPARQL, Fluree has its own query language format called FlureeQL which adds support for some features not exposed via a traditional GQL or SPARQL endpoint, such as historical or block queries. SQL is also supported to a limited extent, at this time.
