When you have an OData API-layer on top of your Mendix database, you can work with the following options documented by Mendix: https://docs.mendix.com/refguide/odata-query-options/
Specifically for the $expand-option in the URL to navigate to an associated entity, Mendix supports up to the following URL’s:
Associated objects can be retrieved by passing the $expand query parameter. For example: /odata/myservice/v1/Employees?$expand=Cars,Address($expand=City) (OData 4) or /odata/myservice/v1/Employees?$expand=Cars,Address/City (OData 3).
In the above example, I will get the Employee-entity with all of its attributes, the associated Car-entity with all of its attributes, the associated Address-entity and all of its attributes, together with the associated City-entity and all of its attributes.
However, I want to have the flexibility to only select the attribute(s) of the associated entity/entities that I need. Not all of them. Which would result in the following (according to official OData.org documentation):
/odata/myservice/v1/Employees?$expand=Cars($select=BrandName),Address($expand=City($select=ZipCode)) (OData v4)
In this example, I’d like to have the Employee-entities with a column for their car’s brandname and the zipcode of their city. Basically, just two columns instead of everything of the car- and city-attributes.
I would advise to have the same option for OData v3.
Thank you!
Kind regards,
Leander
I agree with Leander that this would be a nice feature to include.
If you are looking for a workaround today, you can use a single $select and provide all the fields you want to retrieve. The downside is that you have to provide all the fields for all the associations and the main object you want to retrieve in one statement. Anything you don't provide won't be in the output.
example:
/odata/myservice/v1/Employees?$expand=Cars&$select=EmployeeName,EmplyeeAddress,Cars/BrandName,Cars/Model