Datomic
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Datomic is a database that uses an immutable data model where data is never updated or erased, only added to over time. It uses distributed transactions where transactions are processed serially by transactors and changes are transmitted to peers. Peers cache data and submit transactions, handling queries using a merged view of the cache and latest data from the transactor. The data model consists of immutable datoms that are entities, attributes, values, and the transaction time, allowing queries over time.
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Datomic
- 1. Datomic JP Erkelens @jperkelens Http://github.com/jperkelens
- 2. Disclaimer!! Nearly everything that follows is cribbed from the datomic website: www.datomic.com
- 3. Rationale Database design conventions were created when memory and disk space was limited and expensive Place-oriented programming Records should not be erased when new ones are made
- 6. Peers Library embedded in app Submits transactions to transactor Handles query/caching/data access
- 7. Transactors Process transactions serially Transmit changes Index in background
- 8. Consequences Reads never lock out writes Each peer has own cache Higher memory footprint/quicker responses
- 9. Data Model Data is immutable How? Time. Datom Consists of entity/attr/value/transaction We don't update records or documents We add/remove datoms Minimal Schema
- 10. Programming Model - Queries The Peer pulls data from storage as needed and caches It receives updates from the transactor Queries run from a merged view of the two After a while minimal network activity is needed No strings! (Maps and vectors) Query language – Datalog. Implicit joins
- 11. Programming Model – Time Apps always work on a consistent snapshot of the database Queries are applied to values of the database in time, or windows
- 12. DEEEEEMMMOOOO!!! Additional Resources Www.datomic.com Http://github.com/limadelic/datomic https://github.com/gns24/pydatomic