Rules and Guidelines for Mapplets

A mapplet is a reusable object that you create in the Mapplet Designer. It contains a set of transformations and lets you reuse the transformation logic in multiple mappings. When you use a mapplet in a mapping, you use an instance of the mapplet. Like a reusable transformation, any change made to the mapplet is inherited by all instances of the mapplet.

A mapplet has the following components:                                   

• Mapplet input   : Can be a input transformation or a source definition
• Mapplet output : Each mapplet must contain one or more Output transformations
• Mapplet ports  : consist of input ports from Input  and output Output transformations.

The following list summarizes the rules and guidelines that should be followed while working with mapplets.

•  You can connect an Input transformation to multiple transformations in a mapplet. However, you cannot connect a single port in the Input transformation to multiple transformations in the mapplet.

• An Input transformation must receive data from a single active source.

• An output group can pass data to multiple pipelines in a mapping.

• A mapplet must contain at least one Input transformation or source definition with at least one port connected to a transformation in the mapplet. 

• A mapplet must contain at least one Output transformation with at least one port connected to another transformation in the mapping. 

• You can open or iconize all the transformations in the mapplet and mapping. You cannot edit any of the properties,
  navigate to other folders, or save the repository while the mapplet is expanded.

• When a mapplet contains a source qualifier that has an override for the default SQL query, you must connect all of the source qualifier output ports to the next transformation within the mapplet.

• If the mapplet contains more than one source qualifier, use a Joiner transformation to join the output into one pipeline.

• If the mapplet contains only one source qualifier, you must connect the mapplet output ports to separate pipelines. You cannot use a Joiner transformation to join the output.

• When you edit a mapplet, you might invalidate mappings if you change the mapplet type from passive to active.

• If you delete ports in the mapplet when the mapplet is used in a mapping, you can invalidate the mapping. 

•  Do not change the datatype, precision, or scale of a mapplet port when the mapplet is used by a mapping.

• If you use a Sequence Generator transformation, you must use a reusable Sequence Generator transformation.

• If you use a Stored Procedure transformation, you must configure the Stored Procedure Type to be Normal.

• You cannot include PowerMart 3.5-style LOOKUP functions in a mapplet.

• You cannot include the following objects in a mapplet:

               - Normalizer transformations
               - Cobol sources
               - XML Source Qualifier transformations
               - XML sources
               - Target definitions
               - Pre- and post- session stored procedures
               - Other mapplets

•  Although reusable transformations and shortcuts in a mapplet can be used, to protect the validity of the mapplet, use a copy of a transformation instead. Reusable transformations and shortcuts inherit changes to their original transformations. This might invalidate the mapplet and the mappings that use the mapplet.