Skip to main content

Schema Annotations for Linked Avro Data (SALAD)

Project description

Schema Salad

Salad is a schema language for describing JSON or YAML structured linked data documents. Salad is based originally on JSON-LD and the Apache Avro data serialization system.

Salad schema describes rules for preprocessing, structural validation, and link checking for documents described by a Salad schema. Salad features for rich data modeling such as inheritance, template specialization, object identifiers, object references, documentation generation, and transformation to RDF. Salad provides a bridge between document and record oriented data modeling and the Semantic Web.

Usage

$ pip install schema_salad
$ schema-salad-tool
usage: schema-salad-tool [-h] [--rdf-serializer RDF_SERIALIZER]
                      [--print-jsonld-context | --print-doc | --print-rdfs | --print-avro | --print-rdf | --print-pre | --print-index | --print-metadata | --version]
                      [--strict | --non-strict]
                      [--verbose | --quiet | --debug]
                      schema [document]
$ python
>>> import schema_salad

Documentation

See the specification and the metaschema (salad schema for itself). For an example application of Schema Salad see the Common Workflow Language.

Rationale

The JSON data model is an popular way to represent structured data. It is attractive because of it’s relative simplicity and is a natural fit with the standard types of many programming languages. However, this simplicity comes at the cost that basic JSON lacks expressive features useful for working with complex data structures and document formats, such as schemas, object references, and namespaces.

JSON-LD is a W3C standard providing a way to describe how to interpret a JSON document as Linked Data by means of a “context”. JSON-LD provides a powerful solution for representing object references and namespaces in JSON based on standard web URIs, but is not itself a schema language. Without a schema providing a well defined structure, it is difficult to process an arbitrary JSON-LD document as idiomatic JSON because there are many ways to express the same data that are logically equivalent but structurally distinct.

Several schema languages exist for describing and validating JSON data, such as JSON Schema and Apache Avro data serialization system, however none understand linked data. As a result, to fully take advantage of JSON-LD to build the next generation of linked data applications, one must maintain separate JSON schema, JSON-LD context, RDF schema, and human documentation, despite significant overlap of content and obvious need for these documents to stay synchronized.

Schema Salad is designed to address this gap. It provides a schema language and processing rules for describing structured JSON content permitting URI resolution and strict document validation. The schema language supports linked data through annotations that describe the linked data interpretation of the content, enables generation of JSON-LD context and RDF schema, and production of RDF triples by applying the JSON-LD context. The schema language also provides for robust support of inline documentation.

Project details


Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

schema-salad-2.3.20170302225134.tar.gz (295.6 kB view details)

Uploaded Source

File details

Details for the file schema-salad-2.3.20170302225134.tar.gz.

File metadata

File hashes

Hashes for schema-salad-2.3.20170302225134.tar.gz
Algorithm Hash digest
SHA256 1b161f2dde8ce128bd30ee9758ded9bfa083dd8d22e9fd7de5b57fcff2b77f16
MD5 e79a5e4e15ae3d33f19b9bb9e92b3840
BLAKE2b-256 7e8e63ef2889fb4e46c8d4d6449b31c36c651b28d4adc0e6bfd664e2d049b29b

See more details on using hashes here.

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page