Fetch specific fields in a query

[skyox]

Protection queries are a particular type of MongoDB queries where you can specify fields you want to get in the output.

Another example where the projection parameter is used:
db.writers.find( { "author": "Gaurav Mandes" }, { _id:0, author:1, title:1 } )
In the example above, the _id field is excluded, which automatically gets added, and the title and author fields are displayed.

[art049]

Yes, the beginning of an implementation has been done in #1 .
But in the meantime, after some thoughts I ended up thinking that it would be better to use mongo db views to that end.
The usage with odmantic would be something like this:

class Rectangle(Model):
    length: int
    width: int

LengthView = createView(Rectangle, (Rectangle.length,))
# LengthView is a View object derived from pydantic; containing only the length field
rects = await engine.find(LengthView, Rectangle.width > 10)

On top of this, since we are using mongodb view, it would be as well possible to do something like this:

class RectangleAreaView(View, model=Rectangle):
    area = Rectangle.length * Rectangle.width

This would create a View containing a field computed (db side) from some other of its fields.

[skyox]

Thank you so much

[amr3k]

Sorry, I don't get it!! where is the createView function? how do I use it?

[art049]

It's not there yet but it's in the plans :)

[Azrael-git]

Hello, any updates about this issue? This functionality is very promising I think

[JiaoyangDong]

I second this. I use this features in mongo/mongoose a lot. Would be a very nice feature to add. :)

[fqzhang42]

Any plan to implement this?

[ILugaro]

We need it)

[syedzahed]

Need it