2b:null 2c:["$","title",null,{"children":"About RDF Annotation (4) | James Anderson | Observable"}] 31:T69d,[Dydra](https://dydra.com) records several internal attributes for each quad. When a repository is configured to retain revisions, each quad associates a record ^[0] of the transactions which determined its visibility. For a simple revisioned repository, these are the ordinals of the transaction ordinals which added and removed. For a replicable repository, these would be the respective uuid revision operations. The [external interface](https://api.dydra.com/sparql/request-parameters.html)^[1] to query those repositories which enable this capability permits a temporal constraint to designate a single revision, an interval or a sliding window, which is interpreted to apply the query to one or more snapshots of the repository. The snapshot serves as the source to constitute the dataset to which to apply the SPARQL query as if it were static. The SPARQL 1.1 language, unfortunately, offers no facility with which to address the internal data. As some means to bind and constrain the revision attributes was required in order to repeat the BEAR benchmarks^[2], we introduced logic into the SPARQL compiler to interpret certain filter expression in ways which operated on those attributes. As adequate as that was, it ran counter to the principle, that the scope of a variable binding is most readily understood from its lexical expression. In this regards, as suspect as SPARQL-star may be as a means to express relations between statements, it does provide a concise expression for the relation between a statement and internal attributes. We explore examples of these, below. 32:T472,## filters When combined with a revision interval, the attributes can select statements from arbitrary revisions. For example, given the interval `*--*`, the filter applies to the addressed revision attributes of all matched statements. ``` prefix dydra: prefix dydraOp: prefix time: prefix : select ?subject ?predicate ?object ?predecessorDeletedOrdinal ?addedOrdinal ?deletedOrdinal ?successorAddedOrdinal where { # dydra:met-by is the end of previous visibility # dydra:starts is the current session visibility with modified content # dydra:finishes is the end of current version visibility # dydra:meets is the start of the next version # the added ordinal is 0, then the statements were added for the first time ?subject ?predicate ?object {| dydra:met-by ?predecessorDeletedOrdinal; dydra:starts ?addedOrdinal; dydra:finishes ?deletedOrdinal; dydra:meets ?successorAddedOrdinal |}. filter (?deletedOrdinal = dydraOp:repository-end-ordinal()) } ``` 33:T44c,footnotes = html`

Footnotes

[5] The ontology neglects to include all of the terms which figure in the temporal extension library interface.

[6] "SPARQL-star : AnnotationPattern"

`34:T514,function generateParseExample(description, query, comment = null) { var p = document.createElement('div'); p.style.borderTop = "solid 1px black"; var span1 = document.createElement('span'); span1.innerText = description; span1.style.fontWeight = "bold"; p.appendChild(span1); var pre1 = document.createElement('pre'); pre1.innerText = query; p.appendChild(pre1); var div1 = document.createElement("div"); var span2 = document.createElement('span'); span2.innerText = "yields as SSE"; div1.appendChild(span2); var pre2 = document.createElement('pre'); pre2.innerText = ""; pre2.style.border = "solid 1px grey"; getQuerySSE(query).then(function(text) { pre2.innerText = text; }); div1.appendChild(pre2); p.appendChild(div1); var div2 = document.createElement("div"); var span3 = document.createElement('span'); span3.innerText = "yields as SPARQL algebra"; div2.appendChild(span3); var pre3 = document.createElement('pre'); pre3.innerText = ""; pre3.style.border = "solid 1px grey"; getQueryAlgebra(query).then(function(text) { pre3.innerText = text; }); div2.appendChild(pre3); p.appendChild(div2); if (comment) { var div = document.createElement('div'); div.innerText = comment; p.appendChild(div); } return p; }35:[] 2f:{"id":"098694ad37dab100","slug":"about-rdf-annotation-4","title":"About RDF Annotation (4)","thumbnail":"997ab57efe584a9766fc9018dc06c85147891d9724bc8d19f3e8baa706190ad2","access_level":"public","create_time":"$D2021-11-17T12:54:50.911Z","update_time":"$D2024-08-10T12:34:54.029Z","view_time":null,"first_public_time":"$D2021-11-17T20:51:19.479Z","fork":{"id":"60d4ad75be4bc84e","slug":"blog-template","title":"blog template","owner":{"id":"b452fd69977f5701","login":"lomoramic","name":"James Anderson"}},"stars":0,"starred":false,"owner":{"type":"team","id":"b452fd69977f5701","login":"lomoramic","name":"James Anderson","avatar_url":"https://avatars-next.observableusercontent.com/dc520bbc733259f2913522cf1d50607777b98a3083f290a6f182534561896497","tier":"starter_2024"},"version":176,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"987c90ad70c449c1","login":"lomoramic","name":"James Anderson","avatar_url":"https://avatars-next.observableusercontent.com/dc520bbc733259f2913522cf1d50607777b98a3083f290a6f182534561896497","tier":null}],"members":[{"type":"individual","id":"987c90ad70c449c1","login":"lomoramic","name":"James Anderson","avatar_url":"https://avatars-next.observableusercontent.com/dc520bbc733259f2913522cf1d50607777b98a3083f290a6f182534561896497","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"title":"About RDF Annotation (4)","cells":[{"id":0,"value":"md`# About RDF Annotation (4)\n## for Internal Attributes`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":31,"value":"$31","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":55,"value":"## internal version attributes\n\nAs an idiomatic extension to Dydra support for Allen Intervals ^[3][4],\nthe query processor recognizes several analogues to the terms from the Strabon library\n^[5]\nto indicate the attributes of the transactions associated with a version:\n- `` : the transaction which removed the statement\n- `` : the transaction which subsequently added a statement\n- ``, `` : the transaction which removed the previous version of a statement\n- `` : the transaction which inserted the statement to begin the version\nwhere these appear in a statement's annotation,\nthey bind a variable to the respective attribute.\n\nNote that the `meets` and `metBy` attributes imply a looser relationship that the strbon analogues, in that they do not require direct adjacency.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":73,"value":"## example queries\n\nIn the examples which follow, version attributes are associated with individual statements in the manner proposed for RDF-star\n^[6].\nThe two variants, `[`...`]` and `{|`...`|}`, are equivalent.\n

[nb. this content is generated live from a dev service. should there be issues, please drop us a note.

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":75,"value":"generateParseExample(\"simple annotation\", `\nprefix dydra: \nprefix : \n\nselect ?s ?id\nwhere {\n # dydra:met-by is the end of previous visibility\n # dydra:starts is the current visibility with modified content\n # the added ordinal is 0, then the statements were added for the first time\n ?s a :Product [ dydra:starts ?addedOrdinal;\n dydra:met-by ?deletedOrdinal ]\n filter ( ?deletedOrdinal = ?addedOrdinal )\n}`)\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":108,"value":"generateParseExample(\"multiple annotations\", `\nprefix dydra: \nprefix : \n\nselect ?s ?id\nwhere {\n # dydra:met-by is the end of previous visibility\n # dydra:starts is the current visibility with modified content\n # the added ordinal is 0, then the statements were added for the first time\n ?s a [ :p1 'v1' {| dydra:starts ?p1_added;\n dydra:metBy ?p1_deleted |};\n :p2 'v2' ;\n rdf:object :Product ] {| dydra:starts ?s_added;\n dydra:metBy ?s_deleted |}\n}`)\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":154,"value":"$32","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":170,"value":"The `count`, `min` and `max` attributes offer access to the statement revision statistics.\n\n```\nselect (min(?count) as ?countMin)\n (round(avg(?count)) as ?countAvg)\n (max(?count) as ?countMax)\n (min(?min) as ?minMin)\n (round(avg(?min)) as ?minAvg)\n (max(?min) as ?minMax)\n (min(?max) as ?maxMin)\n (round(avg(?max)) as ?maxAvg)\n (max(?max) as ?maxMax)\nfrom \nwhere {\n ?s ?p ?o {|\n ?count ;\n ?min ;\n ?max\n |}\n}\n```\n","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":37,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":18,"value":"---","pinned":true,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":80,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":2,"value":"import {catalog} from \"@lomoramic/blog-catalog\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":85,"value":"function getQuerySSE(expression) {\n return ( sparqlPost(expression, {\"Accept\": \"application/sparql-query+sse\", \"Content-Type\": \"application/sparql-query\"}) );\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":104,"value":"function getQueryAlgebra(expression) {\n return ( sparqlPost(expression, {\"Accept\": \"application/sparql-query-algebra\", \"Content-Type\": \"application/sparql-query\"}) );\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":83,"value":"sparqlPost = resourceAPI(\"https://dydra.com/system/null\", \"POST\")","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":81,"value":"import { resourceAPI } from \"@datagenous/resource-protocol-library\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W35","stdlib":"1","titling":"auto"}} 30:"$2f:body"