This blog objective is to introduce the basic concept of Data Transformation and Rule Types for field mapping when we perform SAP data migration project. There might be hundreds of documents explaining about what SAP Data Transformation is, as this concept is existed in market since many years. However, I would like to contribute little more by simplifying the Data Transformation concept from business user perspective so that even a beginner can understand the basic logic.

Data Transformation in simple terms means that the process of changing the structure or value of data from legacy system formats to the target system formats.

So the process which we are using to transform the data from the legacy system to target system is called Field Mapping.

There are eight types of Data Transformation Rule Type in terms of Field Mapping point of view which are as below:

1. Number Range
2. Copy (1:1)
3. Default Value
4. Xref
5. Rule
6. Rule Xref
7. Manual Construction
8. Not Used

Here let’s see the respective rule type in detail:

1. Number Range: Number Range is used when mapping a key field that should use a number generated internally or assigned externally by the Target system. For example, a key field such as BP Number, generated by SAP internal sequence number, can be used to populate internal sequence number. SAP would supply the next available incremented number to complete the field.
2. Copy (1:1): Copy is used when mapping a field that is 1:1 value copy from the Legacy system to the Target system. For example, a field ‘Language’ value in the legacy system is same as the Target SAP value by two letters, it can be value Copy (1:1) from the legacy system to SAP.
3. Default Value: The Default Value is used when mapping a field that should use a default value to the Target field. For example, if the Target field should always contain the value “X”, then the field with this default value will be populated as constant value for every record.
4. Xref: The Xref is used when mapping a field that must use value mapping or lookup table that has a single key field. For example, a field ‘Country’ is a mapping object and has its lookup table for legacy and target mapping value list.
5. Rule: The Rule is used when the field mapping for a field is performed by a rule that is requested by the user.
6. Rule Xref: The Rule Xref is used with a lookup table that has multiple key fields when mapping a field that contains values that must be converted before being value mapped.  If the Target lookup table is a multiple key table, the Value Mapping process will concatenate Target values from the multiple key fields into a single field. For example, a field ‘Region’ is a mapping object under the key field combination of ‘Country’, it needs to select the ‘Country’ value first then expand and get ‘Region’ value under the specific country.
7. Manual Construction: The Manual Construction is used when a field that is available in the target system but not existed in legacy system, then it should be manually generated for the missing field value.
8. Not Used: The Not Used is used when a field that is available in the legacy system will not be loaded into the Target system, or the field in predefined load template is not in scope.

Above is the quite simple and easily understanding for Data transformation and Data transformation Rule Types. Please feel free to like and share your feedback on the comment section.