Update Model

When updating a model in the system (using the REST API POST-model), a number of triples are inserted in the datastore.

Let's assume that the sub-component that has to save the model in the datastore received it in a certain time (e.g. with a timestamp 1425399022110, corresponding to the date Tue, 03 Mar 2015 17:10:22 GMT+1:00).

The assumption that no other model is considered at the exact same time is done. Then, a graph with the name containing the timestamp above is created (e.g. http://www.modaclouds.eu/historydb/model/updates/1425400773874).

The graph will contain a number of triples, and these are created using the modaclouds-knowledge-base-api. All the subjects will have the base prefix http://www.modaclouds.eu/rdfs/1.0/entities#.

Another graph with the name associated to the day in which the timestamp is contained (e.g. http://www.modaclouds.eu/historydb/meta/model/updates/1425340800000 for the example above, where 1425340800000 corresponds to the date Tue, 03 Mar 2015 00:00:00 GMT+1:00) is created or used if it already exists. Only one triple is added, and this has as the subject the name of the graph considered before (e.g. http://www.modaclouds.eu/historydb/model/updates/1425400773874), the predicate <mo:timestamp> and the actual timestamp as the object of the triple (e.g. 1425400773874).

Lastly, in the default graph, one tuple is added, with:

the subject that is the URI of the graph (e.g. http://www.modaclouds.eu/historydb/model/updates/1425400773874),
the predicate is the constant mo:timestamp, and
the object is the hour in which the timestamp is contained (e.g. 1425398400000 for the example above, where 1425398400000 corresponds to the date Tue, 03 Mar 2015 17:00:00 GMT+1:00).

Examples of Query

Here are some examples of SPARQL query:

find all the updates of model inserted:

SELECT * {
    ?s <mo:timestamp> ?o
    FILTER (regex(str(?s), "model/updates"))
}

find all the updates of model inserted in a specific hourly timestamp:

SELECT * {
    ?s <mo:timestamp> ?o 
    FILTER (?o = 1425574800000 && regex(str(?s), "model/updates"))
}

find all the updates of model inserted in a range of hourly timestamps:

SELECT * {
    ?s <mo:timestamp> ?o
    FILTER (?o >= 1425574600000 && ?o <= 1425574900000 && regex(str(?s), "model/updates"))
}