L I G ∀ T U R Ǝ

Ligature is a library for working with knowledge graphs written in Rust. This project provides the main traits and structs used by Ligature as well as some helper functions. See related projects for implementations of these APIs. Ligature is heavily influenced by RDF and related standards but attempts to be more general, more flexible, and easier to use.

Status

This project is still very much under development and subject to change quite a bit in the short term while I'm experimenting.

Ligature's Data Model

Dataset { dataset_name: DatasetName, statements: Statement* }
DatasetName { name: String }
Entity { id: u64 }
Attribute { name: String }
Value {
    Entity { value: Entity } |
    StringLiteral { value: String } |
    IntegerLiteral { value: i64 } |
    FloatLiteral { value: f64 } |
}
Statement { entity: Entity, attribute: Attribute, value: Value }
PersistedStatement { statement: Statement, context: Entity }

Datasets

A dataset in Ligature is a named collection of statements. Valid dataset names are currently groups of characters that include _ a-z A-Z 0-9 that can't start with a number and that are separated by single /. This naming convention is likely to change. Even though dataset names might seem like they nest (test/test looks like it is under test) this isn't the case. A dataset is its own unique entity and stands alone from all other datasets. Also, datasets are very different from named graphs in RDF. For example with named graphs blank nodes are shared across graphs in a dataset, but in datasets blank nodes are unique to their dataset.

Entities

Entities in Ligature are simply an object that we can make statements about. Every Entity is defined by an unique id. The new_entity method returns a new Entity that is automatically generated. The new_entity method runs inside a transaction so it is guaranteed to be unique and at the time of creation.

Attributes

Attributes in Ligature are a label that relates two Entities together.

Values

Values in Ligature can either be an Entity or a Literal.

Literals

Literals in Ligature represent an immutable value. Several types are currently supported with plans to add more. Below is a table with the currently supported types.

Statements

A Statement in Ligature is a product type of { entity: Entity, attribute: Attribute, value: Value, context: Entity }.

Contexts

Contexts in Ligature are an unique Entity that represents a given Statement. They allow you to make Statements about Statements.

Building

This project uses cargo for building. See https://rustup.rs/ for instructions on installing the Rust toolchain. See https://doc.rust-lang.org/cargo/ for documentation on cargo in general.

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