A standard data control obtains its data collections and attributes from its underlying data source in the model or business component layer. For example, an application module data control obtains its data collections from the view objects and associated database tables.
For a placeholder data control, instead of data collections, it has placeholder data types. A placeholder data type is analogous to a data collection. It can be dropped onto a page to create complex components such as forms, tables, and trees. It also has a set of attributes that can be dropped onto pages as individual components such as input text, output text, and select choice. Some attributes may be defined as LOVs.
You will define a master-detail data model by adding the categories and products data types to your data control. You will create the categories data type first, then create the product data type, joined to categories in a master-detail relationship.
To begin creating a placeholder data type, you will open the Create Placeholder Data Type dialog.
To open the dialog, in the Data Controls panel, right-click the ProductData node and select Create Placeholder Data Type.
When you create a placeholder data type, you specify attribute names, types, default UI components, and other options. You can create multiple data types for a data control, similar to the multiple data collections in an application module.
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