Adding Attributes With SchemaMapper

Question

After adding SchemaMapper to my workspace, why don't I see any of the new attributes it is supposed to add?

Answer

SchemaMapper doesn't auto-expose attributes created because they are created dynamically based on what fields occur in the source dataset. For example, if you have a schema mapping table that maps:

 a > x b > y c > z

Then you have 2 source features with the following attributes:

 F1: a F2 a,b

The result features are with the new mapped attribute names:

 F1: x F2: x,y

To get access to the x, y or z attributes within the workspace you need to add an AttributeExposer after the SchemaMapper.

AttributeExposer has an import function to allow you to input destination field names from your schema mapping table. Just edit the AttributeExposer parameters and choose import attribute values if you have a column of field names to import (such as from a schema mapping table), or attribute names if you have a row or schema definition that you want to import names from (such as from a table you want to write to).




Note that while Workbench doesn't show dynamic attributes internally in your workspace, FME can still use them. If you have a field in your destination schema, and SchemaMapper has populated that field, it should be written out whether or not it is actually exposed. Conversely, exposing an attribute will not automatically fill it with data if you don't configure your SchemaMapper correctly. Exposing just lets workbench know you expect to have that field and lets you configure other transformers to work with it.



For more information about the SchemaMapper transformer see: SchemaMapper Transformer Tutorial.