Using The Designer Overview - Informatica

A mapping is a set of source and target definitions linked by transformation objects that define the rules for data transformation. Mappings represent the data flow between sources and targets. When the Integration Service runs a session, it uses the instructions configured in the mapping to read, transform, and write data.

Every mapping must contain the following components:

  • Source definition. Describes the characteristics of a source table or file.
  • Transformation. Modifies data before writing it to targets. Use different transformation objects to perform different functions.
  • Target definition. Defines the target table or file.
  • Links. Connect sources, targets, and transformations so the Integration Service can
    move the data as it transforms it.

A mapping can also contain one or more mapplets. A mapplet is a set of transformations that you build in the Mapplet Designer and can use in multiple mappings.

When you add an object to a mapping, you configure the properties according to the way you want the Integration Service to transform the data. You also connect the mapping objects according to the way you want the Integration Service to move the data. You connect the objects through ports.

The Mapping Designer displays objects in three different views:

  • Iconized. Shows an icon of the object with the object name.
  • Normal. Shows the columns in the ports tab and the input and output port indicators.
    You can connect objects that are in the normal view.
  • Edit. Shows the object properties. You can switch between the different tabs and configure the object in this view.

Object Dependency

Some objects in a mapping are also stored as independent objects in the repository:

  • Sources
  • Targets
  • Reusable transformations
  • Mapplets

The mapping is dependent on these objects. When this metadata changes, the Designer and other PowerCenter Client applications track the effects of these changes on mappings. In these cases, you may find that mappings become invalid even though you do not edit the mapping. When a mapping becomes invalid, the Integration Service cannot run it properly, and the Workflow Manager invalidates the session.

The only objects in a mapping that are not stored as independent repository objects are the non-reusable transformations that you build within the mapping. These non-reusable transformations are stored within the mapping only.

Developing a Mapping

Use the following steps as a guideline when you develop a mapping:

  1. Verify that all source, target, and reusable objects are created. Create source and target definitions. If you want to use mapplets, you must create them also. You can create reusable transformations in the Transformation Developer, or you can create them while you develop a mapping.
  2. Create the mapping. Create a mapping by dragging a source, target, mapplet, or reusable transformation into the Mapping Designer workspace, or you can click Mappings > Create from the menu.
  3. Add sources and targets. Add sources and targets to the mapping.
  4. Add transformations and transformation logic. Add transformations to the mapping
    and build transformation logic into the transformation properties.
  5. Connect the mapping. Connect the mapping objects to create a flow of data from sources to targets, through mapplets and transformations that add, remove, or modify data along this flow.
  6. Validate the mapping. Validate the mapping to identify connection or transformation errors.
  7. Save the mapping. When you save the mapping, the Designer validates it, identifying any errors. The Designer displays validation messages in the Output window. A mapping with errors is invalid, and you cannot run a session against it until you validate it.

PowerCenter also provides a tool that you can use to create a template for a PowerCenter mapping and generate multiple mappings from the template. Mapping Architect for Visio provides an Informatica stencil for the Microsoft Office Visio software that contains shapes representing PowerCenter mapping objects. You can use the mapping object shapes to draw the mapping template on the Visio drawing window.

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