mongo_objects: Accessing MongoDB Sub-Documents Through Proxy Objects

Dec 2023 PyChina Chengdu Presentation

No-SQL databases like MongoDB make it easy to store application data in dictionary-like document objects.

Sub-documents are simply child lists or dictionaries saved within a larger parent document. For example,

• a school management system might save students and grades as dictionaries within a "classroom" document
• a shopping cart app could save color choices and inventory within each "item" document

This talk discusses the development of mongo_objects, a Python module that presents MongoDB documents as custom UserDict subclasses, thereby keeping data and code together.

In addition, mongo_objects simplifies access to subdocuments by presenting them as dictionary-like proxy classes that retain the connection to the original parent document.

• Lightweight proxy classes refer all data access back to the parent document maintaining a single source of truth
• Proxy classes support one-to-one and one-to-many relationships from document to subdocument
• All subdocuments can be proxied from a single database document read
• User-defined proxy classes keep subdocument data and methods separate from the parent document

Resources

• PyCon Chengdu 2023 Conference Slides
• Conference Video on Bilibili