Introduce New Transformer to Modify Schema Easily
To expand the application range, I would suggest a new transformer which allows users to modify schema contents - attribute names and data types stored in the "attribute{}" list easily.
The transformer receives schema features, modifies the contents, and then outputs resulting schema features. Required functionalities should be:
- rename attributes (string replace, regex replace)
- add a common prefix/suffix to attributes matching specified condition (or all)
- remove specified prefix/suffix from attributes matching specified condition (or all)
- change case of attributes matching specified condition (or all)
- remove attributes matching specified condition (exact match, starting with, ending with, regex match)
- replace data type of attributes matching specified condition (name and/or original data type)
- add attributes (pairs of name and data type)
more?
The important thing is that the transformer should be a feature-based one. Since every schema feature read by the FeatureReader will have to arrive in the dynamic writer feature type (Schema Sources: "Schema from first feature") before any data feature belonging to the same feature type. If it wasn't so, the worth would be a half.
If the "all in one" would be too complicated, divide the functionalities into 2 - 3 parts, and multiple transformers may be defined for each part.
Hi Mark
The SchemaSetter will take an incoming feature and create a corresponding list attribute. What is being proposed, is how to enable users to define (create and/or modify) this list manually without needing any incoming features, and preferrably with a user friendly interface.
David
Hi @mark_1spatial, my primary intention is to allow users to edit easily existing attribute{} list contained by schema features which have been read by the FeatureReader (<Schema> port, 2015.1+) or Schema (Any Format) reader. A potential use case I most recently found is:
Read dynamic (from sde) and write to dynamic (mapinfo)
Regarding the SchemaSetter, I believe it would be still useful but there are cases where it cannot satisfy user's requirement because it has some limitations, e.g.
- doesn't support some data types such as decimal, date, datetime,
- users cannot control width of character string type,
- will not generate schema definition of missing attributes in the input feature,
and so on.
These limitations cannot be avoided, since the transformer generates schema definition from the input data feature (not schema feature) and a data feature doesn't have enough information for configuring complete schema. The expected transformer might also complement such limitations.
"How about a transformer, e.g. the SchemaCreator, that lets you define the contents of the attribute{} list via the GUI? You could reuse parts of the dialog used for feature type user attributes, e.g.
For the example above, the transformer would output the following attributes (overwriting any existing attribute{}-list):
attribute{0}.name = 'objectid'
attribute{0}.fme_data_type = 'fme_uint32'
attribute{1}.name = 'mystring'
attribute{1}.fme_data_type = 'fme_char(255)'
attribute{2}.name = 'somevalue'
attribute{2}.fme_data_type = 'fme_decimal(10,3)'
attribute{3}.name = 'when'
attribute{3}.fme_data_type = 'fme_datetime'
You could even add a column with the incoming attributes to rename to the newly created schema attributes (think built-in AttributeRenamer)."
