The implementation of a CDH application starts with the design a construction of the application. The work, case and data classes are important for storing the campaigns and data. The strategies are used to store the business logic.  All the rules must be saved in a class, which must be created first.

Understanding the application and classes

A CDH application contains work, data, strategies and case classes.

The application needs data, which you can structure in your data classes. So based on the defined data structure, all data classes needs to be created under the data class.

Configuring the application and classes

If on Pega Cloud, the silent application process will automatically handle this for you. If you find this has not been done, reach out to cloud support. For on-premise customers, continue with the below steps.

Before starting: Access the Organization landing page and create a customer organizational structure. For more information, see the Organization chart tab on the Organization landing page.

1. 1. Create a new Application Setup operator ID by performing the following actions:
   1. Log in by entering the administrator user name with the password that you specified for your application.
   2. Save as a copy of the MKTTemplate:CDHAdministrator access group into your own administrator access group. For the purposes of this document, let’s call this access group CDHAdmin access group.
   3. Save as a copy of the administrator operator ID into a CDHAdmin operator
   4. Add the CDHAdmin access group to the new operator record and set it as the default access group.
   5. On the Work tab, update the organizational unit to point to the organizational structure created as part of prerequisites steps.
   6. Save the new Application Setup operator.
2. Log in as the CDHAdmin operator.
3. In the Dev Studio header, click the name of your current application and click New Application.
4. Follow the instruction in the New Application wizard. For more information, see Creating an application.
5. Click Switch to new application.
6. Optional: To fully set up your application, in the top-right corner of the screen, click Resources menu > Application Guides and follow the setup steps.

The New Application wizard creates the application class structure for you. The classes and rulesets that the wizard creates in your application can be reused. When you implement your applications, you can apply class hierarchy and inheritance principles to help you improve the maintainability and overall efficiency of your application. For more information, see Class layers and class hierarchy and inheritance.

Pega CDH requires a customer class to support the loading of customer data.

1. Define a name for the customer class. For more information, see Creating a class.
2. Identify the customer class key. The default key property is CustomerID.
3. Identify the ruleset for the customer class. For example: <your-application>-Rules
4. Define the PegaMKT-Data-Customer customer class as the directed inheritance parent class to your newly created customer class.
5. Identify the associations (for example, PurchaseData) for this customer class.

Data classes

A standard XCAR (extended customer analytical record) data model is provided for FS and should be used as a baseline. 

You can find Pega provided vertical XCAR data models on Pega Marketplace. If you opt to use a Pega provided vertical XCAR data model, you will need to update the directed inheritance parent class to your newly created customer class with the Pega provided vertical XCAR customer class.[ZH1] 

In the Make customer data available User Story, it is explained how the data model is used, extended, classes are created, and data is mapped against these classes.