The Writer Mode determines which database command should be issued for each feature received. The writer mode is specified at the feature type level only.
Valid writer modes are UPSERT and DELETE.
UPSERT (default)
Features are either inserted or updated based on the value for the Row Identifier attribute. If no value is provided for the Row Identifier, or if the Socrata dataset does not have a Row Identifier, then UPSERT inserts a new row. If the feature type has only a subset of the columns on the corresponding Socrata dataset, updates of existing rows will only update those columns – columns not on the feature type will retain their existing values.
DELETE
Features are deleted according to the Row Identifier. The user attribute that corresponds to the Row Identifier must be present. All other user attributes are ignored. It is an error to use DELETE mode if the dataset does not have a Row Identifier. Rows on the Socrata dataset that do not have a Row Identifier value cannot be deleted.
Note: If a Row Identifier is set on the Socrata dataset, the Socrata DataSync tool will skip features that do not supply a value for the Row Identifier column. However, it is still possible to create rows/features with an empty Row Identifier value via the Socrata web interface.
Specifying the writer mode on a per-feature basis using the fme_db_operation attribute is not supported.