XQuery Sequences

XQuery sequences are used to specify an ordered collection of items. These items can be of similar or different types.

Creating a sequence

An XQuery sequence is created using parenthesis with strings inside quotes or double quotes or numbers. XML elements can also be used as the items of a sequence.

There are two ways to create items of sequence iterated one by one.

Using index
Using values

XQuery Expression for Index

items.xqy

let $items := ('orange', <apple/>, <fruit type="juicy"/>, <vehicle type="car">sentro</vehicle>, 1,2,3,'a','b',"abc")
let $count := count($items)
return
<result>
   <count>{$count}</count>   
   <items>
      {
	     for $item in $items
         return <item>{$item}</item>
      }
   </items>   
</result>

How to run

Create a Java based XQuery executor program to read the items.xqy, passes it to the XQuery expression processor, and executes the expression. After that the result will be displayed.

XQueryTester.java

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import javax.xml.xquery.XQConnection;
import javax.xml.xquery.XQDataSource;
import javax.xml.xquery.XQException;
import javax.xml.xquery.XQPreparedExpression;
import javax.xml.xquery.XQResultSequence;
import com.saxonica.xqj.SaxonXQDataSource;
public class XQueryTester {
   public static void main(String[] args){
      try {
         execute();
      }
      catch (FileNotFoundException e) {
         e.printStackTrace();
      }      
      catch (XQException e) {
         e.printStackTrace();
      }
   }
   private static void execute() throws FileNotFoundException, XQException{
      InputStream inputStream = new FileInputStream(new File("items.xqy"));
      XQDataSource ds = new SaxonXQDataSource();
      XQConnection conn = ds.getConnection();
      XQPreparedExpression exp = conn.prepareExpression(inputStream);
      XQResultSequence result = exp.executeQuery();
       while (result.next()) {
         System.out.println(result.getItemAsString(null));
      }
   }	
}

Execute XQuery against XML

Put the above three files to a same location. We put them on desktop in a folder name XQuery7. Compile XQueryTester.java using console. You must have JDK 1.5 or later installed on your computer and classpaths are configured.

Compile:

javac XQueryTester.java

Execute:

java XQueryTester

Output:

XQuery Expression for Index

items.xqy

let $items := (1,2,3,4,5,6)
let $count := count($items)
return
   <result>
      <count>{$count}</count>  
      <items>
      {
         for $item in $items
         return <item>{$item}</item>
      }
      </items>   
   </result>

Follow the same procedure as above:

Output: