使用XQJ的简单查询

Question

前言: Oracle实现可能不是开源的。解决办法似乎是使用saxonica__。

如何导入OXQDataSource

Oracle使用：

import oracle.xml.xquery.OXQDataSource;

但这是从哪里来的呢？

我不知道要导入什么，也不知道JAR应该在XQJ示例7-1的类路径上从Oracle 文档中导入什么，因为我在尝试编译时获得了error: package oracle.xml.xquery does not exist。

是套餐在java.lang.Object下的XQJ

编译错误，包不存在：

thufir@dur:~/NetBeansProjects/helloWorldBaseX$ 
thufir@dur:~/NetBeansProjects/helloWorldBaseX$ gradle clean run

> Task :compileJava FAILED
/home/thufir/NetBeansProjects/helloWorldBaseX/src/main/java/org/basex/examples/local/App.java:15: error: package oracle.xml.xquery does not exist
import oracle.xml.xquery.OXQDataSource;
                        ^
/home/thufir/NetBeansProjects/helloWorldBaseX/src/main/java/org/basex/examples/local/App.java:46: error: cannot find symbol
        OXQDataSource ds = new OXQDataSource();
        ^
  symbol:   class OXQDataSource
  location: class App
/home/thufir/NetBeansProjects/helloWorldBaseX/src/main/java/org/basex/examples/local/App.java:46: error: cannot find symbol
        OXQDataSource ds = new OXQDataSource();
                               ^
  symbol:   class OXQDataSource
  location: class App
3 errors

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 0s
2 actionable tasks: 2 executed
thufir@dur:~/NetBeansProjects/helloWorldBaseX$ 

带导入的代码：

package org.basex.examples.local;

import java.io.IOException;
import java.util.Properties;
import java.util.logging.Logger;
import javax.xml.xquery.XQConnection;
import javax.xml.xquery.XQException;
import javax.xml.xquery.XQPreparedExpression;
import javax.xml.xquery.XQSequence;
import org.basex.core.BaseXException;
import org.basex.core.Context;
import org.basex.core.cmd.CreateDB;
import org.basex.core.cmd.DropDB;
import org.basex.core.cmd.List;
import oracle.xml.xquery.OXQDataSource;

public final class App {

    private static final Logger LOG = Logger.getLogger(App.class.getName());
    private final Properties properties = new Properties();
    private final Context context = new Context();

    public static void main(String[] args) throws BaseXException, IOException {
        LOG.fine("starting..");
        new App().helloWorld();
    }

    private void list() throws BaseXException {
        LOG.info(new List().execute(context));
    }

    private void helloWorld() throws BaseXException, IOException {
        properties.loadFromXML(App.class.getResourceAsStream("/basex.xml"));
        String databaseName = properties.getProperty("databaseName");
        String databasePath = properties.getProperty("databasePath");

        list();
        new CreateDB(databaseName, databasePath).execute(context);
        list();
        new DropDB(databaseName).execute(context);
        list();

    }

    private void oracleXQJ() throws XQException {
        OXQDataSource ds = new OXQDataSource();
        XQConnection con = ds.getConnection();
        String query = "<hello-world>{1 + 1}</hello-world>";
        XQPreparedExpression expr = con.prepareExpression(query);
        XQSequence result = expr.executeQuery();
        // prints "<hello-world>2</hello-world>"
        System.out.println(result.getSequenceAsString(null));
        result.close();
        expr.close();
        con.close();
    }

}

我只是将导入语句放入其中以生成一个特定的错误。什么应该进口，从什么进口？

只有这一门课给出了问题，原因不明。不知道如何导入，也不知道如何为该导入在类路径上添加什么。

I 看见

The lib directory contains these JAR and ZIP files:

         classgen.jar
         jdev-rt.zip
         oraclexsql.jar
         transx.zip
         xml.jar
         xml2.jar
         xmldemo.jar
         xmlmesg.jar
         xmlparserv2.jar
         xschema.jar
         xsqlserializers.jar
         xsu12.jar

The jlib directory contains these JAR files:

         orai18n.jar
         orai18n-collation.jar
         orai18n-mapping.jar
         orai18n-utility.jar

其中之一，大概是OXQDataSource。

Answer 1

XQJ的设计是从创建表示特定XQuery引擎和数据库的数据源开始，然后建立从应用程序到该数据源的连接，然后使用标准接口对数据源执行查询。原则上，如果要切换到不同的查询引擎，只需实例化不同的数据源即可。因此，如果您想从Oracle切换到Saxon，则实例化Saxon DataSource，而不是Oracle DataSource。