Hello Wagner,
I want to add a calculated field (or more) to a table query in my REST server in order to send it with XData.
It doesn't matter whether I later have to work with a standard query (REST Get List standard endpoint) or a service function.
The entity list passed with XData must therefore be expanded to include the field.
I have no idea what to do.
Thomas
Hello Thomas,
I got confused with the terms. What is "add a calculated field to a table query in my REST Server"?
Are you using an automatic CRUD endpoint or a service operation endpoint?
Are you building a query component manually server-side?
Are you referring to calculate fields in a query component or in an entity class?
Can you please be more specific, I really didn't understand what you want to achieve, thanks.
It is simple,
As an an example: (dummy example)
A table: Name:String / Quantity:Integer / Price:Float
The client application wants to display a table with : Name, Quantity, Price, AND Total:Float (Total = Quantity * Price)
The client application is stupid. The client can only show
The client can use automatic CRUD, but I can also make a service endpoint.
I usually get a TList<TMyEntity>.
But there are only Name,Quantity,Price included.
I'm looking for a quick solution to extend this list with a field/column that is calculated on the server.
And here are the two questions
Currently I have simply extended the entity with the desired fields (also in the database) and calculate the values in Aurelius with OnInserting/OnUpdating. But I really didn't want to add these fields to the database.
Is there another, simpler solution?
There are a few solutions. First is to add calculated fields to your entity. Just create a Total property, set a getter for it and calculate the total based on the getter. Then make such property available in JSON by adding XDataJsonProperty attribute to it. An example:
Another option is to create your own DTO class (TMyDTOEntity) and return it from a service operation. Then create and fill its properties manually from TMyEntity, and fill in the missing properties accordingly.
Thank you, Wagner. Now I have 3 possibilities.
I can choose the best solution for any case.
This topic was automatically closed 24 hours after the last reply. New replies are no longer allowed.