Introduction to data transforms Pega 7

Summary
Use a data transform (known before PRPC 6.2 as a "model rule") to define how to take source data values — data that is in one format and class — and turn them into data of another format and class (the "destination" or "target").

What a data transform does
​Generally speaking, a data transform defines how to take source data values — data that is in one format — and transform them into data of another format (the "destination" or "target"). In PRPC, you can use a data transform to:

• Normalize data for use with a data page.
• Define, copy, or map data with activities.
  • Copying a clipboard page to make a new page.
  • Mapping properties (and their values) on one page to another, existing page.
  • Mapping properties (and their values) on one page to a new page.
  • On a given clipboard page, defining one or more initial properties on that page and setting their values. A data transform can set many property values on a page in one processing step.
  • Appending pages from one Page List property to another.

Using a data transform speeds development and is easier to maintain than setting property values with an activity, because the data transform form and actions are easier to understand than the activity form and methods, especially when the activity includes custom Java code. We recommend using data transforms instead of activities for normalizing and delivering your application data.

Note:  Prior to version 6.2, data transforms were known as model rules, and only involved setting property values. Data transforms now provide more powerful actions than they previously could.

A data transform is a structured sequence of actions. When the system invokes the data transform, it invokes each action in turn, following the sequence defined in the data transform's record form.

The Data Transform record form
​On the data transform's Definition tab, the actions to be taken are presented as a sequence of rows in a tree grid. Except for the conditional types of actions (such as When, For Each Page In, and similar actions) and transitional actions (such as Exit For Eachand similar actions), the system invokes each row in sequence, starting with the first row.
In the example below, the data transform CopyShippingInformationToBilling maps data from the shipping information for an order to the order's billing information.

In general, each row provides for:

​ColumnDescriptionActionAn action to be taken. 
TargetA target, if the action requires a target.
RelationA relation, if the action requires a relation to be specified. This relation is a relationship between the specified target and source.
SourceA source, if the action requires a source.