分享程序员开发的那些事...
更新时间：2022-06-23 05:32:02
正如一些人在此处以及在您之前的类似问题中提到的那样，您可能需要更多地阅读有关 RDF 建模的本质数据.
As a few people have mentioned here and on your similar, previous question, you probably need to do some more reading about the nature of RDF-modeled data.
对于 Stack Overflow，您绝对需要养成显示输入数据和到目前为止编写的任何代码的习惯，即使它不能完美运行.在这种情况下，您需要在问题中包含错误消息.
For Stack Overflow, you definitely need to get into the habit of showing your input data and whatever code you have written so far, even if it isn't working perfectly. In that case, you need to include the error message in your question.
这是一个自包含的示例，其中我
Here's a self contained example in which I
该示例是用 R 语言编写的，这是我最强的语言.需要明确的是:你不需要知道任何关于 R 的知识就能擅长 RDF、SPARQL 和其他语义技术.如果我更擅长 Java 或 Python，我会写一个例子那些语言.
The example is written in R, my strongest language. To be clear: you don't need to know anything about R to be good at RDF, SPARQL and other semantic technologies. If I were better at Java or Python, I would have written the example in one of those languages.
关系 (SQL) 数据必须先转换为 RDF，然后才能使用 RDF 进行查询.在下面的代码中，我是手工完成的.有关螺母和螺栓的信息，请参见消息末尾.
The relational (SQL) data must be converted to RDF before it can be queried with RDF. In the code below, I have done that by hand. See the end of the message for the nuts and bolts.
library(rrdf)
library(sqldf)
mytable.table.string <- 'empid,empname
1,Arthur
2,Kevin
3,Joey'
mytable <- read.csv(textConnection(mytable.table.string))
print(mytable)
> empid empname
> 1 1 Arthur
> 2 2 Kevin
> 3 3 Joey
sqldf('select empname from mytable where empid = 1')
> empname
> 1 Arthur
# R2RML conversion goes here
# I did it by hand
table.rdf.string <- 'prefix mytable: <http://mytable/>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
mytable:1 a mytable:employee .
mytable:1 mytable:empid "1" .
mytable:1 rdfs:label "Arthur" .
mytable:2 a mytable:employee .
mytable:2 mytable:empid "2" .
mytable:2 rdfs:label "Kevin" .
mytable:3 a mytable:employee .
mytable:3 mytable:empid "3" .
mytable:3 rdfs:label "Joey" . '
mytable.rdf <- fromString.rdf(table.rdf.string, format = "TURTLE")
query.as.sparql <- 'prefix mytable: <http://mytable/>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
select ?empname
where
{?emp a mytable:employee .
?emp mytable:empid "1" .
?emp rdfs:label ?empname . }'
sparql.rdf(model = mytable.rdf, sparql = query.as.sparql)
> empname
> [1,] "Arthur"
回顾:上面的这个 R 代码演示了一个 SAPRQL 查询，它相当于 OP 的 SQL 查询.SQL 查询通常针对 SQL 数据库运行，但我通过针对数据帧运行它来使其独立.
To review: this R code above demonstrates a SAPRQL query that is equivalent to the OP's SQL query. SQL queries are typically run against SQL databases, but I made this self-contained by running it against a dataframe.
SPARQL 查询针对 RDF 数据运行，通常以三元组数据库的形式运行.在我的示例中，包含 RDF 三元组的字符串被转换为内存中的 RDF 模型，并将 SPARQL 查询发送到该模型.
SPARQL queries are run against RDF data, frequently in the form of a triplestore database. In my example, a string containing RDF triples is converted into an in-memory RDF model, and the SPARQL query is sent to that model.
那么问题就变成了，如果您在 SQL 数据库中有数据，您如何使用 SPARQL 查询数据库的内容?截至 2017 年夏季，这是一个不断发展的话题.有多种商业和开源工具可以帮助解决此问题，通常采用以下两种方式之一:
So the question becomes, if you have data in a SQL database, how do you query the database's contents with SPARQL? As of Summer, 2017, this is an evolving topic. There are a variety of commercial and open-source tools that can help solve this problem, usually in one of two ways:
无论哪种情况，都需要有人创建从 SQL 数据到 RDF 格式的映射.这是必需的，因为 SQL 表本质上没有显式语义.行通常代表某个类别的个体，而列通常代表个体的属性或关系.RDF 三元组必须具有明确的主谓宾语义.
In either case, somebody will need to create a mapping from the SQL data into RDF format. This is required because SQL tables don't intrinsically have explicit semantics. Rows typically model individuals of some category, and columns typically represent properties or relationships of the individuals. RDF triples must have explicit subject-verb-object semantics.
以下是我推荐的使用 Karma 进行 SQL-RDF 映射的第一步，它有一个很好的图形界面.使用另一个 R2RML 映射器(如 D2RQ(有效，但 3 年未维护)，ontop，或 R2RML 解析器.
Here are my recommended first steps for SQL-RDF mapping with Karma, which has a nice graphical interface. Similar results could be achieved with another R2RML mapper like D2RQ (works, but un-maintained for 3 years), ontop, or the R2RML parser.
44403425.owl 在 Karma 中打开附加本体(import -> from file)mytable.csv，意在表示来自 SQL 数据库的转储.如果您想与直播一起工作数据库，您将负责确保正确的数据库驱动程序已安装.在这种情况下，使用 import -> Database Table
mytable-model.ttl.点击下拉菜单在 Karma 网页顶部附近的灰色条的左侧.选择Apply R2RML model -> from file 并加载mytable_model.ttl
Publish -> RDF.接受建议的设置.OpenRDF.右键点击该链接可在新的浏览器窗口/选项卡中打开它.karma_data 存储库.您现在可以使用左侧的任何 Explore 链接，包括(SPARQL) Query 链接44403425.owl Open the attached ontology in Karma (import -> from file)mytable.csv, which is intended to represent
a dump from a SQL database. If you want to work with a live
database, you will be responsible for making sure the right database
drivers are installed. In that case, use import -> Database Table
instead.mytable-model.ttl. Click on the pull-down
on the left of the gray bar near the top of the Karma web page.
Choose Apply R2RML model -> from file and load mytable_model.ttl
Publish -> RDF. Accept the suggested settings.OpenRDF at the right of the top black bar. Right click
that link to open it in a new browser window/tab.karma_data repository.
You can now use any of the Explore links on the left, including
the (SPARQL) Query link最后，如果您想使用 Karma 以外的 R2RML 映射器，您可以使用类似于(但不完全相同)mytable-model.ttl 的映射文件.Karma 使用嵌入在 JSON 中的 Python 片段进行一些数据操作.该 JSON 成为 km-dev:hasWorksheetHistory 三元组的巨大对象.我不相信所有的 R2RML 解析器都会识别 Python/JSON.
Finally, if you want to use an R2RML mapper other than Karma, you can use a mapping file similar to (but not identical to) mytable-model.ttl. Karma does some data manipulations with snippets of Python, which get embedded in JSON. That JSON becomes the huge object of a km-dev:hasWorksheetHistory triple. I don't believe that all R2RML parsers would recognize the Python/JSON.
44403425.owl
<?xml version="1.0"?>
<rdf:RDF xmlns="https://***.com/questions/44403425.owl/"
xml:base="https://***.com/questions/44403425.owl/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:mytable="https://***.com/questions/44403425.owl/"
xmlns:owl="http://www.w3.org/2002/07/owl#"
xmlns:xml="http://www.w3.org/XML/1998/namespace"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
<owl:Ontology rdf:about="https://***.com/questions/44403425.owl"/>
<owl:DatatypeProperty rdf:about="https://***.com/questions/44403425.owl/empid">
<rdfs:domain rdf:resource="https://***.com/questions/44403425.owl/employee"/>
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:label>employee identifier</rdfs:label>
</owl:DatatypeProperty>
<owl:Class rdf:about="https://***.com/questions/44403425.owl/employee">
<owl:equivalentClass>
<owl:Restriction>
<owl:onProperty rdf:resource="https://***.com/questions/44403425.owl/empid"/>
<owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
</owl:Restriction>
</owl:equivalentClass>
<rdfs:label>employee class</rdfs:label>
</owl:Class>
</rdf:RDF>
mytable.csv
"empid","empname"
1,"Arthur"
2,"Kevin"
3,"Joey"
mytable-model.ttl
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix pato: <http://purl.obolibrary.org/obo/pato#> .
@prefix dc: <http://purl.org/dc/elements/1.1/> .
@prefix obo: <http://purl.obolibrary.org/obo/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix oboInOwl: <http://www.geneontology.org/formats/oboInOwl#> .
@prefix protege: <http://protege.stanford.edu/plugins/owl/protege#> .
@prefix turbo: <http://turbo.org/> .
@prefix subsets: <http://purl.obolibrary.org/obo/ro/subsets#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix rr: <http://www.w3.org/ns/r2rml#> .
@prefix km-dev: <http://isi.edu/integration/karma/dev#> .
_:node1bi2073ftx1 a km-dev:R2RMLMapping ;
km-dev:sourceName "mytable.csv" ;
km-dev:modelPublicationTime "1496863444477"^^xsd:long ;
km-dev:modelVersion "1.7" ;
km-dev:hasInputColumns "[[{\"columnName\":\"empname\"}],[{\"columnName\":\"empid\"}]]" ;
km-dev:hasOutputColumns "[[{\"columnName\":\"empname\"}],[{\"columnName\":\"empid\"}],[{\"columnName\":\"empid_val\"}]]" ;
km-dev:hasModelLabel "mytable" ;
km-dev:hasBaseURI "https://***.com/questions/44403425.owl/" ;
km-dev:hasWorksheetHistory """[
{
\"commandName\": \"SubmitPythonTransformationCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"hNodeId\",
\"type\": \"hNodeId\",
\"value\": [{\"columnName\": \"empid\"}]
},
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"newColumnName\",
\"type\": \"other\",
\"value\": \"empid_val\"
},
{
\"name\": \"transformationCode\",
\"type\": \"other\",
\"value\": \"return getValue(\\\"empid\\\")\"
},
{
\"name\": \"errorDefaultValue\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"isJSONOutput\",
\"type\": \"other\",
\"value\": \"false\"
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid\\\"}]}]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid_val\\\"}]}]\"
}
],
\"tags\": [\"Transformation\"]
},
{
\"commandName\": \"SetWorksheetPropertiesCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"properties\",
\"type\": \"other\",
\"value\": {
\"graphLabel\": \"\",
\"hasBaseURI\": false,
\"prefix\": \"mytable\",
\"hasPrefix\": true,
\"hasServiceProperties\": false
}
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
}
],
\"tags\": [\"Transformation\"]
},
{
\"commandName\": \"SetWorksheetPropertiesCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"properties\",
\"type\": \"other\",
\"value\": {
\"graphLabel\": \"\",
\"hasBaseURI\": true,
\"baseURI\": \"https://***.com/questions/44403425.owl/\",
\"hasPrefix\": false,
\"hasServiceProperties\": false
}
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
}
],
\"tags\": [\"Transformation\"]
},
{
\"commandName\": \"SetWorksheetPropertiesCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"properties\",
\"type\": \"other\",
\"value\": {
\"graphLabel\": \"mytable\",
\"hasBaseURI\": false,
\"hasPrefix\": false,
\"hasServiceProperties\": false
}
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[]\"
}
],
\"tags\": [\"Transformation\"]
},
{
\"commandName\": \"SetMetaPropertyCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"hNodeId\",
\"type\": \"hNodeId\",
\"value\": [{\"columnName\": \"empid\"}]
},
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"metaPropertyName\",
\"type\": \"other\",
\"value\": \"isUriOfClass\"
},
{
\"name\": \"metaPropertyUri\",
\"type\": \"other\",
\"value\": \"https://***.com/questions/44403425.owl/employee\"
},
{
\"name\": \"metaPropertyId\",
\"type\": \"other\",
\"value\": \"https://***.com/questions/44403425.owl/employee1\"
},
{
\"name\": \"SemanticTypesArray\",
\"type\": \"other\",
\"value\": [{
\"DomainUri\": \"https://***.com/questions/44403425.owl/employee\",
\"DomainId\": \"https://***.com/questions/44403425.owl/employee1\",
\"isPrimary\": true,
\"isProvenance\": false,
\"FullType\": \"http://isi.edu/integration/karma/dev#classLink\",
\"DomainLabel\": \"https://***.com/questions/44403425.owl/employee/employee1 (add)\"
}]
},
{
\"name\": \"trainAndShowUpdates\",
\"type\": \"other\",
\"value\": true
},
{
\"name\": \"rdfLiteralType\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"language\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid\\\"}]}]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid\\\"}]}]\"
}
],
\"tags\": [\"SemanticType\"]
},
{
\"commandName\": \"SetSemanticTypeCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"hNodeId\",
\"type\": \"hNodeId\",
\"value\": [{\"columnName\": \"empid_val\"}]
},
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"SemanticTypesArray\",
\"type\": \"other\",
\"value\": [{
\"DomainUri\": \"https://***.com/questions/44403425.owl/employee\",
\"DomainId\": \"https://***.com/questions/44403425.owl/employee1\",
\"isPrimary\": true,
\"isProvenance\": false,
\"FullType\": \"https://***.com/questions/44403425.owl/empid\",
\"DomainLabel\": \"https://***.com/questions/44403425.owl/employee/employee1\"
}]
},
{
\"name\": \"trainAndShowUpdates\",
\"type\": \"other\",
\"value\": true
},
{
\"name\": \"rdfLiteralType\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"language\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid_val\\\"}]}]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empid_val\\\"}]}]\"
}
],
\"tags\": [\"SemanticType\"]
},
{
\"commandName\": \"SetSemanticTypeCommand\",
\"model\": \"new\",
\"inputParameters\": [
{
\"name\": \"hNodeId\",
\"type\": \"hNodeId\",
\"value\": [{\"columnName\": \"empname\"}]
},
{
\"name\": \"worksheetId\",
\"type\": \"worksheetId\",
\"value\": \"W\"
},
{
\"name\": \"selectionName\",
\"type\": \"other\",
\"value\": \"DEFAULT_TEST\"
},
{
\"name\": \"SemanticTypesArray\",
\"type\": \"other\",
\"value\": [{
\"DomainUri\": \"https://***.com/questions/44403425.owl/employee\",
\"DomainId\": \"https://***.com/questions/44403425.owl/employee1\",
\"isPrimary\": true,
\"isProvenance\": false,
\"FullType\": \"http://www.w3.org/2000/01/rdf-schema#label\",
\"DomainLabel\": \"https://***.com/questions/44403425.owl/employee/employee1\"
}]
},
{
\"name\": \"trainAndShowUpdates\",
\"type\": \"other\",
\"value\": true
},
{
\"name\": \"rdfLiteralType\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"language\",
\"type\": \"other\",
\"value\": \"\"
},
{
\"name\": \"inputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empname\\\"}]}]\"
},
{
\"name\": \"outputColumns\",
\"type\": \"hNodeIdList\",
\"value\": \"[{\\\"value\\\":[{\\\"columnName\\\":\\\"empname\\\"}]}]\"
}
],
\"tags\": [\"SemanticType\"]
}
]""" .
km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 a rr:TriplesMap .
_:node1bi2073ftx1 km-dev:hasTriplesMap km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 .
km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx2 rr:tableName "mytable.csv" ;
a rr:LogicalTable ;
km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx1 km-dev:hasLogicalTable _:node1bi2073ftx2 .
km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 rr:logicalTable _:node1bi2073ftx2 ;
rr:subjectMap _:node1bi2073ftx3 .
_:node1bi2073ftx1 km-dev:hasSubjectMap _:node1bi2073ftx3 .
_:node1bi2073ftx3 km-dev:isPartOfMapping _:node1bi2073ftx1 ;
a rr:SubjectMap ;
km-dev:alignmentNodeId "https://***.com/questions/44403425.owl/employee1" ;
rr:class <https://***.com/questions/44403425.owl/employee> ;
rr:template "{empid}" ;
a km-dev:steinerTreeRootNode .
km-dev:PredicateObjectMap_5a63b356-1bbb-4b1f-b64a-514c19f83d28 rr:predicate <https://***.com/questions/44403425.owl/empid> .
_:node1bi2073ftx4 rr:column "empid" ;
a rr:ObjectMap ;
km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx1 km-dev:hasObjectMap _:node1bi2073ftx4 .
km-dev:PredicateObjectMap_5a63b356-1bbb-4b1f-b64a-514c19f83d28 rr:objectMap _:node1bi2073ftx4 .
km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 rr:predicateObjectMap km-dev:PredicateObjectMap_5a63b356-1bbb-4b1f-b64a-514c19f83d28 .
km-dev:PredicateObjectMap_5a63b356-1bbb-4b1f-b64a-514c19f83d28 a rr:PredicateObjectMap ;
km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx1 km-dev:hasPredicateObjectMap km-dev:PredicateObjectMap_5a63b356-1bbb-4b1f-b64a-514c19f83d28 .
km-dev:PredicateObjectMap_028e84af-9ed2-406c-81d0-9add2ed2ca2b rr:predicate rdfs:label .
_:node1bi2073ftx5 rr:column "empname" ;
a rr:ObjectMap ;
km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx1 km-dev:hasObjectMap _:node1bi2073ftx5 .
km-dev:PredicateObjectMap_028e84af-9ed2-406c-81d0-9add2ed2ca2b rr:objectMap _:node1bi2073ftx5 .
km-dev:TriplesMap_d397eb02-1069-4e93-a544-0f2c4d1f8970 rr:predicateObjectMap km-dev:PredicateObjectMap_028e84af-9ed2-406c-81d0-9add2ed2ca2b .
km-dev:PredicateObjectMap_028e84af-9ed2-406c-81d0-9add2ed2ca2b a rr:PredicateObjectMap ;
km-dev:isPartOfMapping _:node1bi2073ftx1 .
_:node1bi2073ftx1 km-dev:hasPredicateObjectMap km-dev:PredicateObjectMap_028e84af-9ed2-406c-81d0-9add2ed2ca2b .