Main subsystems
Parser
Intercepts MediaWiki page parsing to extract
[[Property::Value]] annotations and build a SemanticData object for each page.Store
Abstract layer (
SMW\Store) that persists and retrieves semantic data. Concrete implementations exist for SQL, SPARQL, and Elasticsearch backends.Query engine
Translates SMW query language (
#ask) into backend-specific queries and returns QueryResult objects consumed by result printers.Export
Serializes semantic data to RDF/OWL and other formats for linked-data consumers and the SPARQL store.
Storage backends
SMW ships three interchangeable store implementations, all of which implement the abstractSMW\Store interface.
SQLStore
The default backend, suitable for small and mid-size wikis. Stores semantic data in dedicated MySQL/PostgreSQL/SQLite tables using a subject-predicate-object (SPO) schema.
SPARQLStore
For advanced users who need a triple store and linked-data integration. Semantic data is mirrored to an external SPARQL endpoint (e.g. Blazegraph, Fuseki).
ElasticStore
Recommended for large wiki farms that need to scale or combine structured and full-text search. Stores data in Elasticsearch alongside the SQL tables.
How a page annotation flows through the system
Wikitext parsing
A user saves a page containing
[[Population::517,052]]. MediaWiki invokes the SMW parser hook, which reads the annotation and creates a DataValue from the user input string.DataItem creation
The
DataValue validates and normalizes the input, then produces an immutable DataItem (e.g. DINumber) that represents the canonical, language-independent value.SemanticData assembly
The
DataItem is added to a SemanticData container via addPropertyObjectValue(property, dataItem). The container accumulates all property-value pairs for the current page.Store update
After parsing completes,
Store::updateData(SemanticData) is called. The store fires the SMW::Store::BeforeDataUpdateComplete and SMW::Store::AfterDataUpdateComplete hooks, then delegates to doDataUpdate() in the active backend.Querying
An
#ask query reaches Store::getQueryResult(SMWQuery). The backend translates the query conditions into SQL (or SPARQL/Elasticsearch), executes it, and returns a QueryResult.Development policies
| Policy | Detail |
|---|---|
| No MediaWiki table modifications | SMW creates and manages its own tables exclusively. Writing to the cache is the only exception. |
| No MediaWiki class patching | SMW never modifies, patches, or monkey-patches MediaWiki classes. |
| Hooks and public API only | Integration with MediaWiki is done exclusively through publicly available hooks and API interfaces. |
@private classes are internal | Classes and public methods annotated @private are not part of the public API and may change or be removed without notice. |
| No direct table access | Extensions should use the SMW public API rather than querying SMW tables directly. |
Architecture sub-pages
Data model internals
DataItem hierarchy, SemanticData container, DataValue and DataType layers.
Database schema
Table definitions, SPO pattern, fixed vs. variable property tables.
Coding conventions
PSR-4 namespacing, method ordering, dependency injection, testing requirements.