Declaring a JSON attribute

For declaring a JSON attribute with Pony you should use the Json type. This type can imported from pony.orm package:

from pony.orm import *
db = Database()
class Product(db.Entity):
    id = PrimaryKey(int, auto=True)
    name = Required(str)
    info = Required(Json)
    tags = Optional(Json)
db.bind('sqlite', ':memory:', create_db=True)
db.generate_mapping(create_tables=True)

The info attribute in the Product entity is declared as Json. This allows us to have different JSON structures for different product types, and make queries to this data.