Elephant 1.0 (Alpha 2) A Persistent Object Database for Common Lisp - - PowerPoint PPT Presentation

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

Elephant 1.0 (Alpha 2)

A Persistent Object Database for Common Lisp

by Ian Eslick, MIT Media Lab

also Robert Read, Alex Mizrahi, Henrik Hjelte, and Leslie Polzer,

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

Overview circa 2006

• Fully dynamic typing (blobs, not ORM)
• User-visible btrees and indexes on btrees
• Class slot indexing semantics
• Multiple back-ends (BDB and SQL)
• 5+ years of active use, primarily in commercial

and academic web projects. Also games, web mining, and various research applications.

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

Upcoming Release

• Schema evolution (interesting tradeoffs!)
• Expanded slot semantics
• Persistent sets, duplicate-keyed btrees
• Postmodern based data store

– Why? Licensing and distributed operation

• Simple, prevalence-style data store
• Constraint-based query compiler
• Garbage Collection

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

1.0 Release Platforms

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

Slot Semantics in 1.0

• Transient
• Persistent
• Indexed: value -> instance
• Derived index: (fn obj) -> instance
• Associations (N:1 or N:M)
• Set-valued (API issues)
• Cached (checkout style caching)

Ian Eslick, Research Assistant New Media Medicine / Cognitive Machines MIT Media Lab

ILC’09

http://common-lisp.net/project/elephant

• r

Google for “lisp elephant”