JSON Fields

FastPG includes JSON helpers in fastpg.fields.

JsonData

JsonData is an annotated Pydantic type for JSON-compatible values.

from fastpg import DatabaseModel, JsonData


class Product(DatabaseModel):
    id: int | None = None
    properties: JsonData = {}

    class Meta:
        db_table = "products"
        primary_key = "id"
        auto_generated_fields = ["id"]

Behavior:

• For DB writes (model_dump(context={"db_write": True})), dict/list values are serialized to JSON.
• For normal serialization, Python objects are preserved.

Helper functions

• json_str_to_dict(value): if value is a JSON string, parse it.
• validate_json_data(data): serialize dict/list values for validation flow.
• serialize_json_data(data, info): serializer used by JsonData.

JSON update operators in queryset update(...)

• field__jsonb={...}: replace JSONB column.
• field__jsonb_set__key=value: set one JSON key.
• field__jsonb_remove="key": remove one JSON key.

Example:

await Product.async_queryset.filter(id=1).update(
    properties__jsonb_set__color="blue",
)