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Tips for Adding and Managing Feature Types

The Writer schema defines "what we want" as a destination dataset. So if you want to write data to a particular layer, in a particular dataset, then you have to ensure that the layer is defined as a feature type in the canvas.

In some cases, this happens automatically. When you generate a workspace, the source dataset(s) you choose are scanned and all of the layers within get matching feature type objects in the workspace – both on the Reader and the Writer.

When FME adds Writer feature types as part of a new workspace, those feature types will get a fixed (manual) attribute definition that is taken from the selected source dataset. You can then manually edit these attributes.

However, in most cases you need to manage Writer feature types separately, because what you want from the Writer is not the same as what you have in the Reader. For example, if you want to divide an incoming layer of data into two layers in the output dataset, you will need to add a new Writer feature type.

Adding a Writer feature type manually has this effect on the hierarchy diagram. Your output was designed to have only a single layer; now it will have two.