Quick Start

This quick start provides basic information for getting started with DataDirect XQuery immediately after installation, including the following topics:

In addition, this quick start describes the DataDirect XQuery command-line utility that is available for quickly running and testing XQueries through a console window. See "Using the Command-Line Utility" for details.

For complete information about the many DataDirect XQuery features, read the other chapters in this book.

For information about product requirements, refer to "System and Product Requirements" in the DataDirect XQuery Installation Guide.

For information about getting started with the examples shipped with DataDirect XQuery, see "Examples".

For information about using the DataDirect XML Converters, refer to:
http://www.xmlconverters.com

For information about using Stylus Studio^®, refer to: http://www.stylusstudio.com/xquery/datadirect_xquery.html

For information about getting started with the DataDirect XQuery Editor for Eclipse, refer to:
http://www.xquery.com/xml_tools/eclipse

1. Setting the CLASSPATH

Only one DataDirect XQuery jar file, ddxq.jar, must be defined in your CLASSPATH. The CLASSPATH is the search string your Java Virtual Machine (JVM) uses to locate DataDirect XQuery on your computer. If ddxq.jar is not defined on your CLASSPATH, you receive a ClassNotFoundException exception when trying to use DataDirect XQuery.

where install_dir is the path to your DataDirect XQuery installation directory.

NOTE: If you are connecting to MySQL Community Server or PostgreSQL, you must add the MySQL Connector/J driver jar file and PostgreSQL JDBC driver jar file, respectively, to the CLASSPATH in addition to ddxq.jar. Refer to your MySQL Connector/J driver documentation or PostgreSQL JDBC driver documentation for the name of the jar file.

2. Configuring Connections

DataDirect XQuery provides multiple ways to configure connections to XML data sources and relational data sources (see "Choosing a Connection Method"). This section shows how to use XQJ to create a DDXQDataSource instance in your Java application explicitly.

XML Data Source Connections

If your Java application contains queries that access an XML file, you can directly access the file as shown in the following XQJ code, where the location and name of the XML file is specified as a parameter of fn:doc(), an XQuery function.

DDXQDataSource ds = new DDXQDataSource(); 
XQConnection conn = ds.getConnection(); 
conn.createExpression().executeQuery("doc('path_and_filename')");

Relational Data Source Connections

How you configure connection information for relational databases using XQJ depends on whether you are accessing a single database or multiple databases. This section shows how to configure connection information to access a single database. For information about accessing multiple databases, see "Configuring Connections Explicitly".

To configure a single relational data source connection, use the DDXQDataSource class as shown in the following XQJ code example. This example specifies a connection URL (represented by URL) for the relational data source that you want to access and the user ID and password required to access the relational data source.

DDXQDataSource ds = new DDXQDataSource(); 
ds.setJdbcUrl("URL"); 
XQConnection conn = ds.getConnection("myuserid","mypswd");

The format of the connection URL depends on whether you are using a built-in JDBC driver or a third-party driver, and the database you are connecting to. See "Specifying Connection URLs" for details.

See "Sample Connection URLs" for examples of the minimum information, including any required connection properties, that you must specify in a connection URL.

Sample Connection URLs

The following URLs are examples of the minimum information that must be specified in a connection URL.

jdbc:xquery:db2://server_name:50000;databaseName=your_database

jdbc:xquery:db2://server_name:446;locationName=db2_location

jdbc:xquery:informix://server_name;1526;InformixServer=dbserver_name

jdbc:xquery:sqlserver://server_name:1433

jdbc:mysql://server_name

jdbc:xquery:mysql://server_name

jdbc:xquery:oracle://server_name:1521

jdbc:postgresql:your_database

jdbc:xquery:sybase://server_name:5000

3. Developing a Java Application that Executes a Query

Using DataDirect XQuery, a Java application uses XQJ to execute a query. The Java package name of the XQJ classes is:

The Java class name of the DataDirect XQuery implementation of the XQJ standard interface, XQDataSource, is:

The following sample Java code illustrates the basic steps that an application would perform to execute an XQuery expression using DataDirect XQuery. This example accesses a Microsoft SQL Server data source. To simplify the example, this code does not include error handling.

// import the XQJ classes 
import com.ddtek.xquery3.*; 
import com.ddtek.xquery3.xqj.DDXQDataSource; 
 
// establish a connection to a relational data source 
// specify the URL and the user ID and password 
DDXQDataSource ds = new DDXQDataSource(); 
ds.setJdbcUrl("jdbc:xquery:sqlserver://server1:1433;databaseName=stocks"); 
XQConnection conn = ds.getConnection("myuserid", "mypswd"); 
// create an expression object that is used to execute a query 
XQExpression xqExpression = conn.createExpression(); 
 
// the query 
String es = "for $h in collection('holdings')/holdings " + 
                        "where $h/stockticker='AMZN' " + 
                        "return $h"; 
 
// execute the query 
XQResultSequence result = xqExpression.executeQuery(es); 
result.writeSequence(System.out, null); 
 
// free all resources 
result.close(); 
xqExpression.close(); 
conn.close();