A map associates a source business object with a destination business object, and contains a series of transformation steps--one for each attribute that is being transformed. Each transformation step contains Java code that calculates the value of the attribute.
Within a data map, the conversion of source to destination attributes can be simple, or it can require establishing and maintaining relationships between data entities that are equivalent but are represented differently and cannot be directly transformed.
In a simple case of data transformation, the values of the source and destination attributes have a clear correspondence and similar meanings, although the attributes might be structured differently.
Simple mapping includes actions such as these:
Figure 5-2 is an example of simple mapping for a few of these operations:
Some attributes do not lend themselves to simple transformations. Different applications may have attributes that are equivalent, containing information for a similar purpose, but which have incompatible formats or values. For example, for a Country attribute, one application might use a two-letter code (such as US, FR, or EG) while another application uses a numeral (such as 1, 2, or 3).
To associate such attributes between different applications, you create relationship definitions, associating the data of the source and destination attributes.
When you create a relationship definition, you list the participants (business objects or other data entities) that are involved in the relationship, and you specify a type (either the name of a business object definition or the word Data) for each participant. Based on the types of the participants and the number of instances of each participant that can be related in that definition, relationships are classified into the following categories:
For more information about relationship definitions, start with Chapter 1 of the Map Development Guide.