Crate reindeer

reindeer 🦌 is a small entity-based embedded database with a minimal no-SQL relationnal model, written in pure Rust.

It uses sled, serde and bincode under the hood.

reindeer 🦌 lifts your sled!

It relies on a trait, Entity, to provide basic document store capabilities to any serde-serializable struct that implements it.

To use reindeer, add a key to identify any instance individually to your struct and implement the store_name, get_key and set_key methods to implement the reindeer::Entity trait.

You can then use

• the Entity::save method to save your struct instance to the database
• the Entity::get method to get any entity from the database using its unique key
• the Entity::get_all method to get all entities from the database using its unique key
• the Entity::get_with_filter method to get all entities that match a condition (O(n))
• … And much more!

If the Key associated type is u32, then your entity can be auto-incremented with save_next() from the AutoIncrementEntity (which needs to be in scope)

Three types of relationships can be achieved :

• Sibling relationship : two or more Entity structs that share the same key type for which each entity has 0 or 1 counterpart in their sibling Entity stores (one-to-zero-or-one)
• Parent-Child relationship : An entity has a collection of matching entities in another Entity Store (one-to-many)
• Free relationship : Any two entities can be linked together as a two-way link. (many-to-many)

Those provide integrity checks in the form of a DeletionBehaviour enum, that can either be :

• DeletionBehaviour::Cascade : related entities are also removed if this one is removed
• DeletionBehaviour::Error : Trying to remove this entity as related entities still exist will cause an error and abort
• DeletionBehaviour::BreakLink : Remove this entity and the links with its related entites, leaving the other ones untouched

Structs

Db

sled database struct. It can be copied and used accross threads and is a central item to store entities. This is a re-export of sled::Db.

Error

Error type for reindeer

QueryBuilder

QueryBuilder is a convenient way to build query to target several conditions without the need to immediately serialize/deserialize data from disk. For simplicity’s sake, ids are expressed as &[u8]. To get the key of an entity using this type, just use &entity.get_key().as_bytes().

Enums

DeletionBehaviour

Enum for use in relation description, defining how the database must behave if one end of the relation is removed.

ErrorKind

Error kind enum for Reindeer-related errors.

Traits

AsBytes

Trait allowing values to be converted to Vec<u8>. This trait is not meant to be implemented, but you can if you need to.

AutoIncrementEntity

AutoIncrementEntity is a trait aimed to automatically be implemented on Entities that have u32 as their Key type.

Entity

The Entity trait provides document store capabilities for any struct that implements it.

Functions

open

Opens a sled database to store Entities. The resulting Db object can be copied accross threads. This is a re-export of sled::open.

Type Aliases

Result

Type definition to simplify the use of Result everywhere in the library

Derive Macros

Deserialize

Entity

Derive macro for reindeer’s 🦌 Entity trait.

Serialize