Connect to REST Data in the Denodo Platform

Denodo Platform is a data virtualization product providing a single point of contact for enterprise database data. When paired with the CData JDBC Driver for REST, Denodo users can work with live REST data alongside other enterprise data sources. This article walks through creating a virtual data source for REST in the Denodo Virtual DataPort Administrator.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live REST data. When you issue complex SQL queries to REST, the driver pushes supported SQL operations, like filters and aggregations, directly to REST and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze REST data using native data types.

Create the REST Virtual Port

To connect to live REST data from Denodo, you need to copy the JDBC Driver JAR file to the external library directory for Denodo and create a new JDBC Data Source from the Virtual DataPort Administrator tool.

1. Download the CData JDBC Driver for REST installer, unzip the package, and run the JAR file to install the driver.
2. Copy the JAR File (and license file if it exists) from the installation location (typically C:\Program Files\CData\CData JDBC Driver for REST\lib\) to the Denodo external library directory (C:\Denodo\Denodo Platform\lib-external\jdbc-drivers\cdata-rest-19).
3. Open the Denodo Virtual DataPort Administrator tool and navigate to the Server Explorer tab.
4. Right-click "admin" and select New -> Data source -> JDBC.
5. Configure the JDBC Connection:
   • Name: your choice, e.g.: rest
   • Database adapter: Generic
   • Driver class path: C:\Denodo\Denodo Platform\lib-external\jdbc-drivers\cdata-rest-19
   • Driver class: cdata.jdbc.rest.RESTDriver

   • Database URI: Set this to a JDBC URL using the necessary connection properties. For example,

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

     Information on creating the Database URI follows:

     Built-In Connection String Designer

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

     java -jar cdata.jdbc.rest.jar

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

     See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models REST APIs as bidirectional database tables and XML/JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

     After setting the URI and providing any authentication values, set Format to "XML" or "JSON" and set DataModel to more closely match the data representation to the structure of your data.

     The DataModel 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 REST 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 REST 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.

6. Click the "Test connection" button to confirm the configuration and click Save.

View REST Data in the VirtualPort Administrator Tool

After creating the data source, you can create a base view of REST data for use in the Denodo Platform.

1. Click the "Create base view" button in the newly created VirtualPort (admin.REST).
2. Expand the object tree and select the objects (tables) you wish to import.
3. Click the "Create selected" button to create views of the REST data.
   Optional: Click "Create associations from foreign keys" to define relationships between the objects.
4. With the view(s) created, navigate to a table (cdata_rest_people) in the Server Explorer and double-click the selected table.
5. In the new tab, click "Execution panel" to open a query panel.
6. Customize the query in the "Execute" tab or use the default:

   SELECT * FROM cdata_rest_people CONTEXT ('i18n'='us_est', 'cache_wait_for_load'='true')
   

7. Click Execute to view the data.

With the base view created, you can now work with live REST data like you would any other data source in Denodo Platform, for example, querying REST in the Denodo Data Catalog.

Download a free, 30-day trial of the CData JDBC Driver for REST and start working with your live REST data in Denodo Platform. Reach out to our Support Team if you have any questions.