pydantic-model

To create Pydantic v2 models for API validation, define a Create, Update, and Get model trio with explicit field constraints. Use @field_validator and @model_validator to enforce type safety, enum constraints, and cross-field validation across your API data layers.

Mapping MongoDB documents to Pydantic v2 API models is best achieved by implementing a from_mongo() method. This pattern seamlessly translates MongoDB documents into API-friendly data transfer objects while maintaining strict type safety and validation discipline.

To enforce cross-field validation in Pydantic v2, use the @model_validator decorator. This allows you to define rules that check multiple fields simultaneously, ensuring data integrity and consistency across complex API request models.

Pydantic v2 works effectively with MongoDB integration by using seamless mapping patterns like from_mongo and to_mongo. This combination ensures reliable, reusable data layers that enforce consistent data rules across your services.

You can use @field_validator and @model_validator together in Pydantic v2. Field validators handle individual field constraints, while model validators manage cross-field validation, ensuring comprehensive type safety and data rules across Create, Update, and Get patterns.

When using Pydantic v2 for MongoDB API models, you must maintain a strict export pattern from __init__.py and structure models in specific directory paths. This requires careful organization of Create, Update, and Get trios to ensure reliable data layer reusability.