savior 0.1.2

Flexible immutable entity database

Savior Database

Embedded schema-less database library backed by LMDB.

Currently in development and not stable yet. The interface and disk format may change in future versions without notice. You probably shouldn't use it to store important data.

Permissively licensed with the ISC License.

Goals

• provide a language-neutral disk format
• utilize LMDB's properties like transactions, append-only writes, and zero-copy reads
• provide intuitive schema-less entity modeling and querying interface
• you shouldn't have to know what questions you want to ask about your data before you start storing it

Developer Interface

There are three actions you can perform on entities in a transaction:

• create
• fetch
• update
• query

An entity is conceptually like a dictionary with attributes and values.

A table is an isolated section of the database for storing entities, usually with a similar set of attributes.

Disk Format

All entities of the same type are stored in one inner LMDB database There is no guarantee that entities have a consistent schema.

Entities are stored on disk as a series of timestamped attribute changes.

• key-value entries have the form (uuid, timestamp, attribute) -> value
• uuid is an auto-generated entity ID
• timestamp is an auto-generated timestamp of when the entry was appended
• attribute and value are the updated entity key value entries

Data is not modified for updates, only appended to indicate the entity changed.