diff --git a/docs/storage-backends.md b/docs/storage-backends.md new file mode 100644 index 00000000..bb05e115 --- /dev/null +++ b/docs/storage-backends.md @@ -0,0 +1,154 @@ +# Graph storage backends and feature matrix + +Semantica separates graph modeling from physical storage. LPG backends are accessed through `graph_store` adapters; RDF backends are accessed through `triplet_store` adapters. + +This page is intentionally conservative: it distinguishes between an adapter existing, a feature being generally available with that model, and a backend needing user-supplied wiring. + +## Status labels + +- `built-in`: adapter implementation exists in Semantica core. +- `tested`: covered by automated integration fixtures or tests. +- `example-only`: usable example exists, but support is not asserted by integration tests. +- `interface/BYO`: interface or integration point exists; bring your own backend wiring. + +## Adapter inventory + +| Backend | Model | Adapter | Status | Reference | +| --- | --- | --- | --- | --- | +| Neo4j | LPG | `semantica.graph_store.Neo4jStore` | built-in | `cookbook/introduction/09_Graph_Store.ipynb` | +| FalkorDB | LPG | `semantica.graph_store.FalkorDBStore` | built-in | `docs/reference/graph_store.md` | +| Amazon Neptune | LPG | `semantica.graph_store.AmazonNeptuneStore` | built-in | `cookbook/introduction/21_Amazon_Neptune_Store.ipynb` | +| Apache AGE | LPG | `semantica.graph_store.ApacheAgeStore` | built-in | `docs/graph_stores/apache_age.md` | +| RDF4J | RDF | `semantica.triplet_store.RDF4JStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` | +| Apache Jena | RDF | `semantica.triplet_store.JenaStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` | +| Blazegraph | RDF | `semantica.triplet_store.BlazegraphStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` | +| Anzo | RDF | `semantica.triplet_store.AnzoStore` | built-in | `cookbook/introduction/20_Triplet_Store.ipynb` | +| Oxigraph | RDF | `semantica.triplet_store.OxigraphStore` | built-in | `docs/reference/triplet_store.md` | + +## Feature matrix + +`Yes` means the capability is expected to work with the adapter and graph model. `Partial` means the capability works with model-specific constraints. `BYO` means the user must supply or validate wiring for the backend. + +| Backend | Model | Ingestion | Context graph construction | Reasoning/analytics | Provenance | Known limitations | +| --- | --- | --- | --- | --- | --- | --- | +| Neo4j | LPG | Yes | Yes | Yes | Partial | Provenance and context metadata are stored as node and edge properties; relationship properties and stable node identifiers are required. | +| FalkorDB | LPG | Yes | Yes | Partial | Partial | Redis-based; provenance depends on node/edge properties, and multi-graph isolation depends on the selected graph name. | +| Amazon Neptune | LPG | Yes | Yes | Partial | Partial | Use the property-graph endpoint; AWS auth, VPC, and endpoint configuration can affect local tests. Provenance depends on node/edge properties. | +| Apache AGE | LPG | Yes | Yes | Partial | Partial | Runs through PostgreSQL/AGE; Cypher compatibility and property handling can differ from standalone LPG engines. | +| RDF4J | RDF | Yes | Partial | Partial | Partial | Context separation relies on named graphs; triple-level provenance may require reification or graph-level metadata. `RDF4JStore(repository_id=...)` currently has no effect — the constructor always connects to the `"default"` repository regardless of the value passed; track a fix separately. | +| Apache Jena | RDF | Yes | Partial | Partial | Partial | Named graphs are needed for context separation; backend configuration and transaction behavior matter. | +| Blazegraph | RDF | Yes | Partial | Partial | Partial | Use quads/named graphs for context; IRI stability and graph naming matter for provenance. | +| Anzo | RDF | Yes | Partial | Partial | Partial | Anzo deployments are environment-specific; validate `dataset_uri`/graphmart naming, named-graph support, and provenance mapping. | +| Oxigraph | RDF | Yes | Partial | Partial | Partial | Embedded, single-process store (in-memory or on-disk); named graphs are supported, but there is no separate server process to scale independently. | + +## RDF and LPG differences + +- LPG backends store context and provenance as graph elements and properties. If a backend does not support relationship properties, some provenance patterns may be degraded. +- RDF backends rely on IRIs, named graphs, and optional reification. Context graphs and provenance are easiest to preserve when the store supports named graphs/quads. +- Ingestion works across both models, but the physical representation differs: LPG stores nodes/edges directly, while RDF stores subject-predicate-object statements. +- Reasoning and analytics should be validated against the adapter's query capabilities, especially for path traversal, property filters, and named-graph queries. + +## Minimal connection examples + +Prefer the referenced notebook cells for a working setup. The examples below show the intended adapter entrypoints, not a universal connection DSL. + +### Neo4j + +```python +import os +from semantica.graph_store import Neo4jStore + +store = Neo4jStore( + uri='bolt://localhost:7687', + user='neo4j', + password=os.environ['NEO4J_PASSWORD'] +) +``` + +### FalkorDB + +```python +from semantica.graph_store import FalkorDBStore + +store = FalkorDBStore( + host='localhost', + port=6379, + graph_name='semantica' +) +``` + +### Amazon Neptune + +```python +from semantica.graph_store import AmazonNeptuneStore + +store = AmazonNeptuneStore( + endpoint='your-neptune-cluster-endpoint', + port=8182, + region='us-east-1' +) +``` + +### Apache AGE + +```python +from semantica.graph_store import ApacheAgeStore + +store = ApacheAgeStore( + connection_string='host=localhost dbname=agedb user=postgres password=postgres', + graph_name='semantica' +) +``` + +### RDF4J + +```python +from semantica.triplet_store import RDF4JStore + +store = RDF4JStore( + endpoint='http://localhost:8080/rdf4j-server', + repository_id='semantica' # currently has no effect; connects to "default" (see Known limitations) +) +``` + +### Apache Jena + +```python +from semantica.triplet_store import JenaStore + +store = JenaStore( + endpoint='http://localhost:3030/ds' +) +``` + +### Blazegraph + +```python +from semantica.triplet_store import BlazegraphStore + +store = BlazegraphStore( + endpoint='http://localhost:9999/blazegraph/sparql' +) +``` + +### Anzo + +```python +from semantica.triplet_store import AnzoStore + +store = AnzoStore( + endpoint='http://anzo-host:8080', + dataset_uri='http://cambridgesemantics.com/Graphmart/your-graphmart-id' +) +``` + +### Oxigraph + +```python +from semantica.triplet_store import OxigraphStore + +# Omit `path` for an in-memory store; pass a directory for on-disk persistence. +store = OxigraphStore(path='./semantica-oxigraph-data') +``` + +Replace hostnames, ports, repositories, graphs, and credentials with values from your environment. For regulated or self-hosted deployments, keep credentials in environment variables or secret storage rather than source code.