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我有一個具有一些VCARD數據的Apache Jena數據庫。我想制定一個查詢,這將返回如何使用SPARQL獲取數據庫中所有人員的暱稱和電子郵件?
- 電子郵件地址和
- 暱稱
數據庫中的每個用戶。
我嘗試這樣做:
SELECT ?nick ?email
WHERE {
?x <http://www.w3.org/2001/vcard-rdf/3.0#EMAIL> ?email,
?x <http://www.w3.org/2001/vcard-rdf/3.0#N> ?n {
?n <http://www.w3.org/2001/vcard-rdf/3.0#NICKNAME> ?nick
}
}
當我嘗試運行此查詢,我得到了以下錯誤消息:
org.apache.jena.query.QueryParseException: Encountered " <IRIref> "<http://www.w3.org/2001/vcard-rdf/3.0#N> "" at line 4, column 32. Was expecting one of: "values" ... "graph" ... "optional" ... "minus" ... "bind" ... "service" ... "filter" ... "{" ... "}" ... ";" ... "," ... "." ...
什麼是查詢正確的版本?