Initiate Database and Define Model¶

Initiate Database and Create Collection¶

There is no need to create a database or collection separately. MongoDB automatically creates a new database and collection while we insert new data.

You need to define a Pydantic model that should inherit Document from mongodb_odm. When new insertion takes place, MongoDB automatically creates everything if something does not exist.

Target¶

First, we will create a Player Document model class.
Define indexes.
Make sure everything is working and has an impact on the database.

Here's a collection structure that we want to achieve.

{
  "_id": ObjectId('id'),
  "name": "Pelé",
  "country_code": "BRA",
  "rating": null
}
{
  "_id": ObjectId('id'),
  "name": "Diego Maradona",
  "country_code": "ARG",
  "rating": 97
}
{
  "_id": ObjectId('id'),
  "name": "Zinedine Zidane",
  "country_code": "FRA",
  "rating": 96
}

Create the Document Model Class¶

The first thing we need to do is create a class to represent the data in the collection.

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

# Code omitted below

Full file preview

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

    class ODMConfig(Document.ODMConfig):
        collection_name = "player"

Import Document from mongodb_odm. Define the Player model that should use Document as the parent class.

Define the collections and fields¶

The next step is to define the fields of the class by using standard Python type annotations.

The name of each of these variables will be the name of the field in the collection. And the type of each of them will also be the type of collection field.

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

# Code omitted below

Full file preview

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

    class ODMConfig(Document.ODMConfig):
        collection_name = "player"

Field declaration¶

Start with the field name defined as type str, which is the standard way to declare something with type in Python.
We declare country_code with type str and in our database it will be stored as a string type.
In the end, we define rating. Notice that it has a type of Optional[int]. And we import that Optional from the typing standard module. The rating field can be null or int in the database.

Primary key¶

You may notice we did not define the primary key.
We use MongoDB default primary key _id as our primary key.
You can access id and _id (PrivateAttr) both should share the same value.

Model ODMConfig¶

The ODMConfig class inside the Player is a special class.

We will use this ODMConfig class to change the configuration of the Player class.

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

    class ODMConfig(Document.ODMConfig):
        collection_name = "player"

Custom Collection Name¶

By default, the collection name of the Player model will be player. The model name will be converted to snake case.

But we can customize the default behavior by defining collection_name in the ODMConfig class.

from typing import Optional

from mongodb_odm import Document


class Player(Document):
    name: str
    country_code: str
    rating: Optional[int] = None

    class ODMConfig(Document.ODMConfig):
        collection_name = "player"