Create a Data Access Object for XML Data using JDBI

JDBI is a SQL convenience library for Java that exposes two different style APIs, a fluent style and a SQL object style. The CData JDBC Driver for XML integrates connectivity to live XML data in Java applications. By pairing these technologies, you gain simple, programmatic access to XML data. This article explains how to build a basic Data Access Object (DAO) and the accompanying code to read and write XML data.

Create a DAO for the XML people Entity

The interface below declares the desired behavior for the SQL object to create a single method for each SQL statement to be implemented.

public interface MypeopleDAO {
 //insert new data into XML
 @SqlUpdate("INSERT INTO people ([ personal.name.last ], [ personal.name.last ]) values (:[ personal.name.last ], :[ personal.name.last ])")
 void insert(@Bind("[ personal.name.last ]") String [ personal.name.last ], @Bind("[ personal.name.last ]") String [ personal.name.last ]);

 //request specific data from XML (String type is used for simplicity)
 @SqlQuery("SELECT [ personal.name.last ] FROM people WHERE [ personal.name.last ] = :[ personal.name.last ]")
 String find[ personal.name.last ]By[ personal.name.last ](@Bind("[ personal.name.last ]") String [ personal.name.last ]);

 /*
 * close with no args is used to close the connection
 */
 void close();
}

Open a Connection to XML

Collect the necessary connection properties and construct the appropriate JDBC URL for connecting to XML.

Connecting to Local or Cloud-Stored (Box, Google Drive, Amazon S3, SharePoint) XML Files

CData Drivers let you work with XML files stored locally and stored in cloud storage services like Box, Amazon S3, Google Drive, or SharePoint, right where they are.

Setting connection properties for local files

Set the URI property to local folder path.

Setting connection properties for files stored in Amazon S3

To connect to XML file(s) within Amazon S3, set the URI property to the URI of the Bucket and Folder where the intended XML files exist. In addition, at least set these properties:

• AWSAccessKey: AWS Access Key (username)
• AWSSecretKey: AWS Secret Key

Setting connection properties for files stored in Box

To connect to XML file(s) within Box, set the URI property to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect to Box.

Dropbox

To connect to XML file(s) within Dropbox, set the URI proprerty to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect to Dropbox. Either User Account or Service Account can be used to authenticate.

SharePoint Online (SOAP)

To connect to XML file(s) within SharePoint with SOAP Schema, set the URI proprerty to the URI of the document library that includes the intended XML file. Set User, Password, and StorageBaseURL.

SharePoint Online REST

To connect to XML file(s) within SharePoint with REST Schema, set the URI proprerty to the URI of the document library that includes the intended XML file. StorageBaseURL is optional. If not set, the driver will use the root drive. OAuth is used to authenticate.

Google Drive

To connect to XML file(s) within Google Drive, set the URI property to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect and set InitiateOAuth to GETANDREFRESH.

The property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

• Document (default): Model a top-level, document view of your XML data. The data provider returns nested elements as aggregates of data.
• FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
• Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

See the Modeling XML Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the XML JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.xml.jar

Fill in the connection properties and copy the connection string to the clipboard.

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

A connection string for XML will typically look like the following:

jdbc:xml:URI=C:/people.xml;DataModel=Relational;

Use the configured JDBC URL to obtain an instance of the DAO interface. The particular method shown below will open a handle bound to the instance, so the instance needs to be closed explicitly to release the handle and the bound JDBC connection.

DBI dbi = new DBI("jdbc:xml:URI=C:/people.xml;DataModel=Relational;");
MypeopleDAO dao = dbi.open(MypeopleDAO.class);

//do stuff with the DAO

dao.close();

Read XML Data

With the connection open to XML, simply call the previously defined method to retrieve data from the people entity in XML.

//disply the result of our 'find' method
String [ personal.name.last ] = dao.find[ personal.name.last ]By[ personal.name.last ]("Roberts");
System.out.println([ personal.name.last ]);

Write XML Data

It is also simple to write data to XML, using the previously defined method.

//add a new entry to the people entity
dao.insert(new[ personal.name.last ], new[ personal.name.last ]);

Since the JDBI library is able to work with JDBC connections, you can easily produce a SQL Object API for XML by integrating with the CData JDBC Driver for XML. Download a free trial and work with live XML data in custom Java applications today.