RDF source¶

The RDF data source is able to read RDF data in N-Triples, Turtle, N3 or RDF/XML format and turn this into entities.

See the Working with RDF document for more detail on working with RDF in Sesam.

It will transform triples on the form <subject-uri> <predicate-uri> "value" OR <object-uri> into entities on the form:

{
    "_id": "<subject-uri>",
    "<predicate-uri>": "value" OR "~robject-uri"
}

RDF Blank Nodes (aka BNodes) will be turned into child entities.

Prototype¶

{
   "type": "rdf",
   "system": "url--or-microservice-system-id",
   "url": "url-to-rdf-file",
   "sort_lists": true,
   "format": "nt-ttl-or-xml"
}

Properties¶

Property	Type	Description	Default	Req
`system`	String	The ID of the URL system or microservice system component to use.		Yes
`url`	String	The URL of the `RDF` file to load - it can contain multiple subjects (with `blank node` hierarchies) and each unique non-blank subject will result in a single root entity.		Yes
`format`	String	The type of `RDF` file referenced by the `url` property. It is an enumeration that can take following recognized values: `"nt"` for N-Triples, `"ttl"` for Turtle, `"n3"` for N3 or `"xml"` for `RDF/XML` files.	“nt”
`sort_lists`	Boolean	If the `sort_lists` is set to `true` any resulting entity properties containing lists of values (due to them having the same RDF predicate) will be sorted, making the output predictable. This applies in a recursive fashion.	true
`is_sorted`	Boolean	Indicates that the input data is sorted on RDF subject. If the `is_sorted` is set to `true` and the `format` property is `nt` (N-Triples), the RDF source will attempt to parse the input data sequentially and emit a new entity when the RDF subject changes, without loading the entire RDF file into memory first. Note that the input data cannot contain RDF Blank Nodes (aka BNodes) in this case. The property has no effect on formats other than `nt`.	false
`if_source_empty`	Enum<String>	Determines the behaviour of the pipe when the RDF source does not return any entities. Normally, any previously synced entities will be deleted even if the pipe does not receive any entities from its source. If set to `"fail"`, the pipe will automatically fail if the source returns no entities. This means that any previous entities in the pipe’s dataset are not deleted. If set to `"accept"`, the pipe will not fail and any previously synced entities will be deleted. The global default `global_defaults.if_source_empty` can be set for all pipes in the service metadata.	`"accept"`

Continuation support¶

See the section on continuation support for more information.

Property	Value
`supports_since`	`false` (Default)
`is_since_comparable`	`true` (Default)
`is_chronological`	`false` (Default)

Example configuration¶

The outermost object would be your pipe configuration, which is omitted here for brevity:

{
    "source": {
        "type": "rdf",
        "url": "http://www.snee.com/rdf/elvisimp.rdf",
        "format": "xml",
    }
}

Merge datasets source

REST source