how to switch collection when query document

[regainOWO]

i want to query collection dota_label and coco_label which collection field is the same from Labels classes, only collection name is diffrent, when i use my example is down here, it only get the query result from dota_label collection

from mongoengine import Document, StringField, BinaryField, ListField, FloatField, DictField


class Images(Document):
    name = StringField(max_length=256, required=True)
    data = BinaryField(required=True)
    file_type = StringField(db_field="fileType", default=str())

    meta = {
        'collection': '_images',
        'allow_inheritance': True
    }


class Labels(Document):

    name = StringField(max_length=256, required=True)
    data = ListField(field=DictField(), default=list(dict()))
    version = FloatField(default=1.0)

    meta = {
        'collection': '_labels',
        'allow_inheritance': True
    }


def main():
    # dota_labels collection
    Labels._meta.update(collection='dota_labels')
    # dota_images collection
    Images._meta.update(collection='dota_images')
    # query
    images_dota = Images.objects()
    labels_dota = Labels.objects()
    """change collection to query"""
    # coco_labels collection
    Labels._meta.update(collection='coco_labels')   # no impact
    # coco_images collection
    Images._meta.update(collection='coco_images')   # no impact
    # query
    images_coco = Images.objects()
    labels_coco = Labels.objects()


if __name__ == '__main__':
    main()

[bagerard]

There s no built-in support for this and this sounds like a rabbit hole I'd rather not explore.

If you just have a need for a few collections, you can use something like:

class ImageFieldsMixin:
        name = StringField(max_length=256, required=True)


class CocoImage(ImageFieldsMixin, Document):
    meta = {
        'collection': 'coco_images',
    }


class DotaImage(ImageFieldsMixin, Document):
    meta = {
        'collection': 'dota_images',
    }