UUID, Email & DateTime

UUID, Email, DateTime & Other Scalars

PyGo provides built-in validated scalar types for common use cases:

• UUID: Universally Unique Identifier (v4 by default)
• Email: RFC 5322-compliant email address
• DateTime: ISO 8601 datetime with timezone awareness
• URL: Validated URL string
• Phone: Validated phone number string
• Decimal: Decimal type for precise arithmetic

All scalar types are validated at compile time and generate idiomatic Go and Python code.

UUID

Definition

model User:
  id: UUID          # Auto-generated v4 UUID
  name: String

Generated Code

Go:

type User struct {
    ID   string  `json:"id"`
    Name string  `json:"name"`
}

Python:

import uuid

class User(BaseModel):
    id: uuid.UUID
    name: str

Database Representation

CREATE TABLE user (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name TEXT NOT NULL
);

Email

Definition

model Contact:
  email: Email
  name: String

Validation

Emails are validated at compile time:

# Valid
contact = Contact(email="user@example.com", name="Alice")

# Invalid — compile-time error
# contact = Contact(email="not-an-email", name="Bob")

Format: local-part@domain (RFC 5322 compliant)

Generated Code

Go:

type Contact struct {
    Email string `json:"email"`
    Name  string `json:"name"`
}

Python:

class Contact(BaseModel):
    email: str  # validated on assignment
    name: str

DateTime

Definition

model Event:
  title: String
  started_at: DateTime
  ended_at: DateTime?

Auto-generated Timestamps

model Article:
  title: String
  created: DateTime = now()    # Set on creation
  updated: DateTime?           # Optional, updated manually

Timezone Handling

All DateTime fields store timezone-aware datetimes in UTC by default:

event = Event(
    title="Launch",
    started_at="2024-01-15T09:00:00+05:00"  # Timezone-aware
)

# Internally stored as UTC
# event.started_at → 2024-01-15 04:00:00 UTC

Generated Code

Go:

import "time"

type Event struct {
    Title    string
    StartedAt time.Time
    EndedAt   *time.Time
}

Python:

from datetime import datetime

class Event(BaseModel):
    title: str
    started_at: datetime
    ended_at: Optional[datetime] = None

Database Representation

CREATE TABLE event (
    id INTEGER PRIMARY KEY,
    title TEXT NOT NULL,
    started_at TIMESTAMP WITH TIME ZONE,
    ended_at TIMESTAMP WITH TIME ZONE
);

URL

Definition

model Website:
  url: URL
  name: String

Validated URL string (e.g., https://example.com/path).

Phone

Definition

model Contact:
  phone: Phone
  name: String

Validated phone number string (e.g., +1-555-123-4567).

Decimal

Definition

model Product:
  name: String
  price: Decimal

Precise decimal type for financial calculations.

Generated Code

Go:

type Product struct {
    Name  string
    Price string  // Decimal stored as string for precision
}

Python:

from decimal import Decimal

class Product(BaseModel):
    name: str
    price: Decimal

Combining with Other Types

Optional Scalars

model Profile:
  user_id: UUID
  secondary_email: Email? = None
  last_login: DateTime? = None

Array of Scalars

model Group:
  name: String
  member_ids: Array[UUID]

Type Summary

Type	Python Type	Go Type	DB Type
UUID	uuid.UUID	string	UUID
Email	str (validated)	string	TEXT
DateTime	datetime	time.Time	TIMESTAMP
URL	str	string	TEXT
Phone	str	string	TEXT
Decimal	Decimal	string	TEXT

Best Practices

• Always use UUID as primary keys — never auto-increment integers
• Validate emails at the model level, not at the controller layer
• Store all datetimes in UTC — convert to local time only for display
• Use Decimal for monetary or precise numerical values
• Use Email? for optional email fields