Fields

Basics

Every model public attributes are automatically set as table columns. You can customize and extend the fields using ardilla.Field and ardilla.ForeignField.

ardilla.Field is actually just a convenience import as it is actually pydantic.Field.

ardilla.ForeignField is an instance of a callable class that serves as a helper for foreign key constrains.

Usage

To extend the functionality of an ardilla.Model import ardilla.Field and use it on your fields. The special keywords to use with fields are:

• default: Sets the default value for the field
• pk: sets the field as the primary key of the table
• auto: sets the field to be autogenerated on insertion. It's only valid for these field types:
• INTEGER: auto applies "autoincrement" and it's only available when used on private keys
• DATETIME, TIME and DATE: auto applies "current_timestamp", "current_date" or "current_time"
• If auto was used, then the field is automatically not required.
• unique: sets the field's value to be unique in the table, it will rise conflic errors if breached

from datetime import datetime
from ardilla import Model, Field

class User(Model):
    id: int = Field(pk=True, auto=True)
    name: str = Field(unique=True)
    age: int # not null field
    money: float = 0.0
    created_date: datetime = Field(default_factory=datetime.utcnow, auto=True)

This Model will generate the following table schema:

CREATE TABLE IF NOT EXISTS user(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL UNIQUE,
    age INTEGER NOT NULL,
    money REAL DEFAULT 0.0,
    created_date DATETIME DEFAULT CURRENT_TIMESTAMP
);

Or, as a table:

id	name	age	money	created_date
1	chris	35	-10	1988-05-27-7

Foreign key support

To set fields with foreign keys, use the foreign field helper ardilla.ForeignField

from ardilla import Model, Field, ForeignField

class Author(Model):
    id: int = Field(pk=True, auto=True)
    name: str

class Book(Model):
    name: str
    author_id: int = ForeignField(
        references=Author, # the model with the referenced key
        on_delete=ForeignField.CASCADE,
        on_update=ForeignField.SET_NULL
    )

This will generate the following schema for the Book model:

CREATE TABLE IF NOT EXISTS book(
    name TEXT NOT NULL,
    author_id INTEGER NOT NULL,
    FOREIGN KEY (author_id) REFERENCES author(id) ON UPDATE SET NULL ON DELETE CASCADE
);

Next

To put your models to use you'll need a an engine...