This page provides an overview of the Façade-X specification documents. Façade-X is the (meta-)model resulting from the abstraction of all the basic data structures used to represent source data formats, combined into a unified model. RDF languages can implement it to provide users with direct access to external, heterogeneous data formats without requiring format-specific transformations.
This document is currently in active development.
Modern data landscapes are inherently heterogeneous: CSV files, JSON documents, spreadsheets, XML, and many other formats each impose their own structural conventions. Façade-X addresses this fragmentation by identifying the minimal set of structural primitives — containers, slots, and values — that are sufficient to faithfully represent any of these formats within a single, coherent model.
The model is intentionally abstract. A container generalises both ordered lists and associative maps; a slot is the allotted place for a value or a nested container, identified either by a cardinal number (a NumberSlot) or by a string key (a StringSlot). This small vocabulary, together with a precisely stated set of logical axioms, constitutes the metamodel from which format-specific RDF mappings are derived.
This repository contains two companion specification documents:
the formal metamodel, expressed in first-order logic, and the RDF vocabulary that realises it
under the namespace http://sparql.xyz/facade-x/ns/.
This document provides the formal definition of the Façade-X metamodel using first-order logic axioms. It introduces and specifies the following concepts:
This document specifies the RDF realisation of the Façade-X metamodel.
It defines the vocabulary terms under the fx: namespace
(http://sparql.xyz/facade-x/ns/), including:
fx:Container — the class of containers.fx:Slot, fx:SlotNumber, fx:SlotString — the slot hierarchy.fx:Value — the class of primitive values.fx:Type — the class of types assignable to containers.fx:Root — the type of the unique top-level container of a data source.