Data Model

Foreign Keys[03]

AllegroGraph does not allow for user-defined consistency rules (like, say, foreign key constraints in a relational database)

Isolation Levels[03]

Every transaction sees a snapshot of the persistent database state as of the time when the transaction is started. During the transaction, it can change the persistent state without affecting the snapshot of others. When finishes, any updates made by concurrent transactions are visible.

Logging[04][05]

When the commit operation of AllegroGraph returns, the database server will have written the updates made by the transaction to the transaction log and waited for the log I/O operation to finish. Transaction log files record all committed database changes (triple additions and deletions), along with some other information.

Query Compilation

Query Interface

RESTful HTTP API, SPARQL

Storage Architecture

Storage Model

Graph / RDF

Stored Procedures

JavaScript or Common Lisp

System Architecture

Views[06][07]

A logic view is offered by Prolog. Query can support match graph ( contains multiple triples), join, filter, order, etc.