How to Prepare for the Denodo Platform 7.0 Certified Developer Exam

The Denodo Platform 7.0 Certified Developer (DEN70EDUCD) exam tests developers’ knowledge of the Denodo Platform and validates if they have the skills required by companies that use Denodo Platform 7.0.

DEN70EDUCD aims to provide organizations that use Denodo Platform 7.0 with a means of identifying suitably qualified staff for designing, developing, and deploying real projects with the Denodo Platform

This exam covers the following technical topics and subject areas:

 

The Principles of Data Virtualization

In this section the examinee should demonstrate that they understand the basic concepts of data virtualizacion:

  • The Current Data Problem
  • Data Virtualization: The Basic Definition
  • The Principles of Data Virtualization
  • Data Virtualization Use Cases
How to prepare

This is a theoretical section that covers the basic definition, principles and use cases of data virtualization. 

To start preparing for this section we recommend that you visit the Denodo Site where you can find helpful content, such as:  A Data Virtualization Overview, How It Works, Benefits and Data Virtualization Solutions.

Next step is to start reviewing the Denodo Community tutorial, the introduction includes a definition of the common data problems that organizations face nowadays and how they can be solved using data virtualization.

All the content related to this section is included in the topic “Data Virtualization. Introduction” which is included in the official Denodo course Data Virtualization Essentials.

Denodo Architecture and Components

This section covers the basic concepts and an overview of the Virtual DataPort Administration and Scheduler tool. The examinee should have some knowledge on the following topics:

  • Data Access Layer
    • Wrappers
    • Base Views
  • Data Integration Layer
    • Derived Views
    • How VDP Works When a Query is Received
  • Data Publishing Layer
    • How to Access the Created Virtual Schema
  • Basic Concepts
    • Basic VQL
    • Data Definition
    • Primary Keys
    • Folders
    • Associations
    • Query Execution

How to prepare

This section is mainly theoretical, it is important to have a good understanding of the Virtual DataPort and Scheduler Architectures including the different layers and the basic concepts related to the Virtual Data Port.

The first step you should take is to review the official documentation that explains the General Architecture of the Virtual DataPort and Scheduler. In this section, the physical layer, logical layer and user layer are explained in detail. 

The best way to start learning about the basic concepts of the Virtual DataPort is to review the first steps section of the tutorials which is available in the Denodo Community.

This section also includes the basic concepts of primary keys and associations.

These concepts are included under the topics “Virtual DataPort. Architecture”, “Scheduler. Architecture” and “Virtual Data Port. Basic Concepts” included in the official Denodo course: Data Virtualization Essentials.

The Denodo Administrations Tools

This section covers all the options and menus that are available in the Virtual DataPort Administration Tool.

The main areas that are covered in this section are:

  • Starting Up the Virtual DataPort Server
  • Virtual DataPort Administration Tool
    • How to Start the Tool
    • Main Areas
    • Folders
    • Available Data Sources
    • Available Operations
    • Publishing Views
    • Quick Search
    • Administration Menu
    • Tools Menu
  • Scheduler Administration Tool
    • Accessing the system
    • Configuring scheduler server
    • Main sections
    • Managing projects
How to prepare

The best way to prepare for this section is by using the Virtual DataPort and Scheduler Administration tools and trying out different options. Here are the main options of the administration tools and the links to the official documentation:

 

In order to launch the the Virtual DataPort server and the admin tool, we recommend that you read the “Installation And Execution” section. You can find this information for the Scheduler admin tool in the “Installation And Execution” section.

All the available options of the Virtual DataPort and Scheduler administration tools are explained in the topics “Virtual DataPort Administration tool” and “Scheduler Administration tool” included in the official Denodo course Data Virtualization Essentials.

Connecting to Data Sources

This section contains all the information on the possible data sources that you can connect to using the Denodo Platform. It  also contains further information on the creation and configuration of base views.

How to prepare

In order to prepare for this section properly, it is preferable that you have practical experience. You can gain the necessary experience by completing various tutorials available in the Denodo Community. You can start by creating a JDBC data source and base views which is covered in the Connecting to Sources tutorial.

Next, there is an example in the Virtual DataPort Administration Guide which explains how to create different data sources and base views graphically, starting with JDBC and web services data sources.

The creation of data sources and base view is very similar, it is simply a case of changing the connection parameters. Once you have understood this process, you can review every data source in more detail in the administration tool or in the Virtual DataPort Administration guide.

As well as the basic way of creating the different data sources, we recommend that you also review the following information related to this section:

We recommend that you create a data source and a base view of every type to check the necessary configuration and understand what is required for each data source.

Finally, it is important to note that this section contains questions related to the topic of JMS listeners. It’s a good idea to try configuring a JMS listener in the Virtual DataPort Administration tool for yourself to understand how works.

All these elements are explained in more detail  in the topics “JDBC”, “ODBC”, “Web Services”, “Delimited Files”, “JSON / XML”, “Excel” and “Path Types in Data Sources” in the official course Data Virtualization Developer (Introduction).

Views in Virtual DataPort

The Denodo Virtual DataPort uses VQL (Virtual Query Language) for data definition and data manipulation. VQL enables administrators to create and update the elements that constitute the system catalog, as well as enabling them to query and update the unified information views. The examiner should be familiar with VQL.

Please note: VQL supports two types of sentences: DDL and DML.

  • DDL (Data Definition Language): is used to create and manage views. For example: CREATE, DROP, ALTER, DESC…
  • DML (Data Manipulation Language): is like SELECT, which enables query execution and the definition of derived views.

Virtual DataPort supports normal queries, but it also contains a set of predefined stored procedures and enables users to import custom developed Java stored procedures.

How to prepare

The examinee should be able to understand the VQL language. The best way to prepare for this section is to create different elements and execute different queries in the VQL Shell of the Virtual DataPort Administration tool. This is a list of all the main parts of the VQL language:

All the information related to VQL is contained in the guide “Virtual DataPort VQL Guide”. The Data Virtualization Developer (Intermediate) and Data Virtualization Developer (Advanced) courses also contains all the information related to this section under the topics “Executing Views” and “View Management”.

Combining Data Sets

This section contains questions about how to create derived views, which combine data from different sources.

The following sections describe the process of creating the following types of views using our example to illustrate the process:

  • Selection Views
  • Union Views
  • Join Views
  • Flatten Views
  • Intersect Views
  • Minus Views

How to prepare

The examinee should be able to understand all the available operations in Virtual DataPort and how to configure them. The best way to understand how to create different derived views is create a view of every type. These are all the operations that are contained in this section:

All these operations are explained in the topics “Operations. Unions”, “Operations. Selection & Projection”, “Operations. Aggregation”, “Operations. Joins”, “Functions” and “Compound types” included in the official Denodo courses: Data Virtualization Developer (Introduction) and Data Virtualization Developer (Intermediate).

Linking Data and Data Services

This section contains questions related to accessing the views created in Virtual DataPort. It includes questions about how to publish REST and SOAP web services, Denodo RESTful Web Services, and clients that can be used to consume the data.

How to prepare

This section can be divided in three sections:

  1. Publishing web services: This part contains questions about how to publish SOAP and REST Web services. The best way to prepare for this section is to publish and configure a few views and consuming data from these views by calling the created web services.
    • SOAP Web Service: We recommend creating this type of web service, publishing different views, and calling them using SoapUI. Other important aspects of this type of web service that should be reviewed are the created WSDL, the configuration of input/output fields, and advanced configuration.
    • RESTful Web Services: The best way to gain practical experience with this is to practice creating RESTful web services, publishing different views, and reviewing how they can be called using the different available formats (HTML, JSON, XML, RSS). Other parts that should be reviewed are how to configure input/output fields, advanced configuration, and URL format.

  2. Denodo RESTful Web Services and Associations: The RESTful web service of the Denodo Platform is an HTTP service that publishes the contents of the entire Virtual DataPort server. We recommend that you access this web service and review the following:
    • The types of resources exposed by the RESTful web service
    • How to invoke the RESTful web service
    • The URI format of the RESTful web service
    • HTTP methods and their equivalent VQL statements
    • Associations represent relationships between views. Users can navigate through associations using navigation queries or the RESTful web service. The best way to understand associations is to create them and then use navigational queries and the RESTful web service to understand how to navigate between associated views.
  3. Client access to Virtual DataPort: Finally, exam takers should know other ways to access the virtual data layer. The most important ways to execute queries to the Virtual DataPort server are:
    • Access through JDBC: We recommend that you connect with the Virtual DataPort server using a database tool like DBVisualizer.
    • Access through ODBC: To test this connection we recommend that you use an ODBC client like WinSQL.
    • Web services (as explained above).

All this information is included in the topics “Data Services”, “Data Services. SOAP”, “Data Services. REST”, “Associations” and “Denodo Restful WS” in the official course Data Virtualization Developer (Intermediate).

Denodo Platform Cache

Virtual DataPort incorporates a system called a “cache module”, which can store a local copy of the data retrieved from data sources in a JDBC database. The questions in this section relate to information about how to configure, load, and perform maintenance on the cache module.

How to prepare

The configuration of the cache database is done in the Server Administration menu; the exam taker should understand:

To understand the cache module, we recommend that you enable the cache and change the configuration, understanding the results in every case.

Information related to the cache database is included in the topics “Cache” and “Denodo Scheduler for Cache” in the course Data Virtualization Developer (Advanced).

Issues Troubleshooting and Logs

This is an important section for administration, you should be able to understand the logs and how to resolve issues.

How to prepare

To be able to handle any potential issues that arise when using the Denodo Platform, an administrator should understand the following:

The Denodo Scheduler

This section is related to the Denodo Scheduler, which enables the scheduling and execution of data extraction and integration jobs, as defined in the different modules of the Denodo Platform.

How to prepare

The exam taker should review the following aspects of Scheduler:

All the information related to Scheduler is contained in the “Scheduler Administration Guide.” The best way to understand this module is to create different jobs (one of each type), executing queries, and exporting data from these queries.

All the information related to Scheduler is included in the topic “Denodo Scheduler” in the course Data Virtualization Developer (Intermediate).

Organizing Teams

The final section of this exam is related to organize your developments with your team, for example, database management, user management and roles.

How to prepare

The Virtual DataPort includes several ways to organize a team, the most important of which are:

All this information is available in the sections entitled “Data Virtualization Project Management” and “Development with Version Control Systems” in the course Data Virtualization Developer (Advanced).

Data Modeling

This section covers top-down design, and to be able to apply this design, Virtual DataPort provides Interface views. Interface views are a special type of view that consists of only a definition of fields and a reference to another view. Therefore, top-down design is where you first define the fields of the interface and then associate the “implementation view” of the interface at a later stage.

How to prepare

The best way to prepare for this section is understand how to create, configure, and implement an Interface view, and to do that, we recommend that the exam taker practices creating, configuring, and implementing different Interface views. The section Creating Interface Views contains all the relevant information.

All the content related to this section is included in the topics “Top-Down vs. Bottom-up modeling” and “Interface views” in the official Denodo course Data Virtualization Developer (Intermediate).

Security in Denodo

The final section of this exam is related to security, for example, database management, publishing data services, SSL / TLS, Kerberos and other security mechanisms.

How to prepare

The Virtual DataPort includes advanced security options, the most important of which are:

To understand more about security, you can check Denodo Security Overview and Kerberos Configuration and Troubleshooting.

All this information is available in the section entitled “Security: Connection to Data Sources” and “Security: Publishing Data Services” in the course Data Virtualization Developer (Advanced).

Optimizations in Denodo

This section contains questions related to the optimization of queries and performance.

How to prepare

To understand performance optimization, exam takers should understand the following Virtual DataPort features:

  • Execution Trace
  • Query Delegation
  • Join Strategies
  • Cache
  • Memory Usage

To understand query optimization, examinees should familiarize themselves with the following topics:

Information related to optimization is included in the topics “Denodo Query Optimizer”, “Automatic Performance Optimizations” and “Development of Query Optimizations” in the course Data Virtualization Developer (Advanced).

Data and Metadata management in Denodo

This section covers advanced view management and data governance in Virtual DataPort.

Regarding advanced view management, the exam taker should have a good knowledge of the following topics:

  • Cache
  • Memory
  • Internationalization Configuration
  • Search Methods
  • Indexes
  • Statistics
  • Execution Plan

The exam taker should be aware of all the Denodo tools related to data governance:

  • Tree View
  • Used by
  • Source Refresh
  • Change Impact Analysis
  • Data Lineage

How to prepare

The exam taker should have a good knowledge of the following areas of advanced view management and data governance:

We highly recommend that candidates review all the documentation and try changing the configuration to understand the differences between options.

Use of the above tools should be reviewed in the Virtual DataPort Administration tool, to better understand how to use them and when.

All this information is included in the topics “Data Management”, “Metadata Documentation” and “Metadata Management” in the course Data Virtualization Developer (Advanced).

Conclusions

In this document, we have reviewed all the sections that are part of the Denodo Platform 7.0 Certified Developer  exam with details and links to the official documentation. As we have indicated in different sections, the best way to understand the Denodo Platform and to acquire practical experience is creating and configuring the different parts that we have explained in every section.

 

Here is a summary of all the resources that are available for preparing for the Denodo Platform 7.0 Certified Developer   exam, which we have used in the explanation of every section:

Denodo Community

The Denodo Community is where customers, partners, and users have access to information that can help them learn about the Denodo Platform and data virtualization. To earn a Denodo certification, begin by following these steps to start learning about data virtualization:

  1. Complete the tutorials. These tutorials offer the first steps to learning about data virtualization and the Denodo Platform.
  2. View the free videos. These videos offer help with specific topics.
  3. Explore the technical articles in our knowledge base.
  4. Get deeper knowledge with the official manuals.

Denodo Training

We recommend that professionals looking to achieve a Denodo certification start by looking at our Denodo training offers on the Denodo Education Site.

These training courses will prepare you for the certification exam:

  1. DEN70EDUG01: Data Virtualization Essentials: This course is aimed to those who don't have previous experience with data virtualization. It provides with concepts, terminology and skills needed before starting any data virtualization project.
  2. DEN70EDUD01: Data Virtualization Developer (Introduction): This course teaches data developers the data virtualization concepts, terminology, and skills required to develop their first Denodo data virtualization project.
  3. DEN70EDUD02: Data Virtualization Developer (Intermediate): This course teaches data developers additional data virtualization concepts, terminology, and skills needed to develop and deploy Denodo data virtualization projects. Topics include the concepts of linked data and top-down development and how to connect from external applications.
  4. DEN70EDUD03: Data Virtualization Developer (Advanced): This course provides data developers with advanced knowledge about data virtualization techniques and teaches best practices needed to get the most out of Denodo data virtualization projects.

Sample Questions

After reviewing all the materials, these are some example of questions that can be found in the Denodo Platform 7.0 Certified Developer exam:

Virtual DataPort is a global solution for the real-time integration of…
1. ... structured data sources.
2. ... heterogeneous, distributed and structured data sources.
3. ... heterogeneous, distributed, structured, and semistructured data sources.
4. Virtual DataPort is not a global solution.

How do you deploy a view to the Denodo RESTful web service?
1. Each created view will be automatically deployed to the Denodo RESTful.
2. You need to activate this feature in the Advanced options of your view.
3. You need to first create a REST Web Service on top of the view.
4. Only cached views are deployed to the Denodo RESTful.

A DF data source can be used to:
1. ...connect to a comma delimited file, although the delimiter can be any character.
2. ...access any text file with a known format that can be expressed as a regular expression.
3. ...access Excel files in .xls format for Excel versions previous to 2013.
4. ...only access CSV files.

Do you have to click into the "Use group by" option to create a new aggregation view?
1. Yes, in all cases.
2. Yes, but only for "Selection" views.
3. Yes, but only for "JDBC" views.
4. No. For instance you can create a select count(*) from view - without explicitly specify group by clause.

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