A Simple Schema

We will be using the Schema class from marshmallow to specify the fields for the objects that we want to serialize/deserialize. Without knowing the schema of the objects and how we want to serialize the fields, we can't perform serialization or deserialization. In the following example, you can see we have a simple SimpleSchema class, which extends marshmallow.Schema, and there are two fields defined there, id and username:

from marshmallow import Schema, fields
class SimpleSchema(Schema):
    id = fields.Int() 
    username = fields.String()

The data type of the fields are defined using the marshmallow fields. From the preceding example, the id field is an integer, while the username field is a string. There are a number of different data types in marshmallow, including Str, Int, Bool, Float, DateTime, Email, Nested, and so on.

With the schema specified, we can start doing object serialization and deserialization...