Two separate paths to the same collection

[Michał Weskida]

Hello,
I am trying to extract data from a collection with two different paths - some fields by connecting collections: A -> B -> C -> D and other fields with a path A -> C.

How can I achieve that?

[Radosław Miernik]

It's not possible at the moment, due to connection mechanism: it can handle trees, not even DAGs. Although, I have an idea for the API. When defining relations, collection names will be either a real (database) names or some kind of aliases. Then all you'll need to do will be providing a mapping from aliases into real names.

Example:

const pipeline = build({
    projection: {
        x: 'A1.x',
        y: 'A2.y'
    },
    // Not present <=> real name.
    // This key name is just an idea.
    real: {A1: 'A', A2: 'A'},
    relations: [
        {
            from: 'S',
            to: 'A1',
            foreign: '_id',
            local: '_id'
        },
        {
            from: 'S',
            to: 'A2',
            foreign: '_id',
            local: '_id'
        }
    ],
    start: 'S'
});

What do you think?

[Michał Weskida]

Seems like a great idea! Can't wait until it's ready :)