Introduction to Asami

Asami is a simple in-memory graph database. It was initially built as an in-memory graph for Naga, but now exists in it's own project. The principal API is through the Storage protocol defined in naga-store.

Asami does not (yet) have a rich set of features, but attempts to keep the major components modular, and relatively simple.

Layout

core

The asami.core namespace is where the main APIs for interacting with Asami are found. For now, these are:

• MemoryStore: A record type that implements the naga.store/Storage protocol.
• empty-store: An instance of MemoryStore, ready to insert data.
• empty-multi-store: An instance of MemoryStore that implements a multigraph (multiple edges are recorded), ready to insert data.
• q: A query function, with the same syntax as the Datomic q function, but fewer features.

query

The asami.query namespace is where the query implementation appears. This includes query planning, and execution. Planning and execution are separate operations, despite being related, and so this namespace is expected to split soon.

graph

The asami.graph namespace defines the Graph protocol. This is a simple triple-only interface for abstracting storage. The graph-diff function is unused for most applications and may be considered optional. It identifies entities whose attributes have changed from one graph to another.

I am hoping to finish a durable storage implementation, based on a design that Mulgara was working towards.

index

The principle implementation of asami.graph. This uses indices of nested maps, terminating at sets.

multi-graph

Alternative multi-graph implementation of asami.graph. Multi-graphs are the same as graphs, but record how many times an edge has been inserted.

Indices of Nested maps, terminating at a statement count. This should be generalized to a map that contains metadata for the statement (and include a count).

asami-util

Central utility namespace. At this point, it contains c-eval and fn-for.

c-eval was used as a portable (Clojure and ClojureScript) eval function for bindings and filters in queries. However, some self-hosted ClojureScript environments have difficulty with evaluation, so another approach is now being used.

fn-for is a portable function for finding functions by symbol. If no namespace is given, then it defaults to looking in clojure.core.

Talks

• Presentation at ClojureD, February 23, 2019. Animated slides. PDF (includes speaker notes).