Inconsistent string typing in SPARQL JSON results #1361
Description
Hello,
When results are returned as application/sparql-results+json, the datatype of strings is inconsistent depending on character content.
If the string contains only ASCII characters, no datatype is added.
If it includes non-ASCII characters, the datatype http://www.w3.org/2001/XMLSchema#string is attached.
This inconsistency causes issues further down the line (e.g DELETE) as Virtuoso does not treat both forms as equivalent.
Virtuoso version
Virtuoso Open Source Edition (Column Store) (multi threaded)
Version 7.2.10.3237-pthreads as of Jul 12 2023 (000000)
Compiled for Linux (x86_64-pc-linux-gnu)
Copyright (C) 1998-2023 OpenLink SoftwareBelow are steps to reproduce the issue.
Let us know if you're able to reproduce it on your side.
Thanks!
Step: insert the data
INSERT DATA {
GRAPH <http://debug> {
<http://test/1> <http://bar> "België spelled correctly".
<http://test/2> <http://bar> "Belgie spelled incorrectly".
}
}Step: check the data with ASCII-only
SELECT DISTINCT ?s ?p ?o WHERE {
GRAPH <http://debug> {
?s ?p ?o
}
VALUES ?s {
<http://test/2>
}
VALUES ?p {
<http://bar>
}
VALUES ?o {
"Belgie spelled incorrectly"
}
}Return as XML 🆗
<sparql
xmlns="http://www.w3.org/2005/sparql-results#"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd">
<head>
<variable name="s"/>
<variable name="p"/>
<variable name="o"/>
</head>
<results distinct="false" ordered="true">
<result>
<binding name="s">
<uri>http://test/2</uri>
</binding>
<binding name="p">
<uri>http://bar</uri>
</binding>
<binding name="o">
<literal>Belgie spelled incorrectly</literal>
</binding>
</result>
</results>
</sparql>Return as application/sparql-results+json 🆗
{
"head": {
"link": [],
"vars": [
"s",
"p",
"o"
]
},
"results": {
"distinct": false,
"ordered": true,
"bindings": [
{
"s": {
"type": "uri",
"value": "http://test/2"
},
"p": {
"type": "uri",
"value": "http://bar"
},
"o": {
"type": "literal",
"value": "Belgie spelled incorrectly"
}
}
]
}
}Step: check the data with non-ASCII
SELECT DISTINCT ?s ?p ?o WHERE {
GRAPH <http://debug> {
?s ?p ?o
}
VALUES ?s {
<http://test/1>
}
VALUES ?p {
<http://bar>
}
VALUES ?o {
"België spelled correctly"
}
}Return as XML 🆗
<sparql
xmlns="http://www.w3.org/2005/sparql-results#"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd">
<head>
<variable name="s"/>
<variable name="p"/>
<variable name="o"/>
</head>
<results distinct="false" ordered="true">
<result>
<binding name="s">
<uri>http://test/1</uri>
</binding>
<binding name="p">
<uri>http://bar</uri>
</binding>
<binding name="o">
<literal>België spelled correctly</literal>
</binding>
</result>
</results>
</sparql>Return as application/sparql-results+json ❌
{
"head": {
"link": [],
"vars": [
"s",
"p",
"o"
]
},
"results": {
"distinct": false,
"ordered": true,
"bindings": [
{
"s": {
"type": "uri",
"value": "http://test/1"
},
"p": {
"type": "uri",
"value": "http://bar"
},
"o": {
"type": "typed-literal",
"datatype": "http://www.w3.org/2001/XMLSchema#string",
"value": "Belgi\\u00EB spelled correctly"
}
}
]
}
}