fiftyone.core.odm.sample

Backing document classes for fiftyone.core.sample.Sample instances.

Class hierarchy:

SerializableDocument
├── NoDatasetSampleDocument
└── DatasetSampleDocument
    ├── my_custom_dataset
    ├── another_dataset
    └── ...

Design invariants:

• A fiftyone.core.sample.Sample always has a backing _doc that is an instance of fiftyone.core.odm.document.SerializableDocument
• A fiftyone.core.dataset.Dataset always has a backing _sample_doc_cls that is a subclass of DatasetSampleDocument

Implementation details

When a new fiftyone.core.sample.Sample is created, its _doc attribute is an instance of NoDatasetSampleDocument:

import fiftyone as fo

sample = fo.Sample()
sample._doc  # NoDatasetSampleDocument

When a new fiftyone.core.dataset.Dataset is created, its _sample_doc_cls attribute holds a dynamically created subclass of DatasetSampleDocument whose name is the name of the dataset's sample collection:

dataset = fo.Dataset(name="my_dataset")
dataset._sample_doc_cls  # my_dataset(DatasetSampleDocument)

When a sample is added to a dataset, its _doc attribute is changed from type NoDatasetSampleDocument to type dataset._sample_doc_cls:

dataset.add_sample(sample)
sample._doc  # my_dataset(DatasetSampleDocument)