191 lines
5.7 KiB
Python
191 lines
5.7 KiB
Python
"""
|
|
How to Use PostgreSQL Models
|
|
|
|
This module provides examples of how to use the base models and database sessions
|
|
effectively in your application.
|
|
"""
|
|
|
|
from datetime import datetime
|
|
from typing import Optional, List
|
|
from sqlalchemy import String, Integer
|
|
from sqlalchemy.orm import Mapped, mapped_column
|
|
|
|
from Services.Postgres.Models.my_base_model import CrudCollection
|
|
from Services.Postgres.database import get_db
|
|
|
|
|
|
# Example Model Definition
|
|
class User(CrudCollection):
|
|
"""Example user model demonstrating CrudCollection usage."""
|
|
|
|
__tablename__ = "users"
|
|
|
|
# Additional fields (id and other common fields come from CrudCollection)
|
|
username: Mapped[str] = mapped_column(String(50), unique=True, index=True)
|
|
email: Mapped[str] = mapped_column(String(100), unique=True)
|
|
age: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
|
|
|
|
|
|
# Example Usage
|
|
|
|
|
|
def example_create():
|
|
"""Example of creating a new record."""
|
|
with get_db() as db:
|
|
# Create a new user
|
|
user = User.find_or_create(
|
|
db, username="john_doe", email="john@example.com", age=30
|
|
)
|
|
db.commit()
|
|
return user
|
|
|
|
|
|
def example_batch_create():
|
|
"""Example of creating multiple records in a single transaction."""
|
|
with get_db() as db:
|
|
try:
|
|
# Create multiple users in one transaction
|
|
users = []
|
|
for i in range(3):
|
|
user = User.find_or_create(
|
|
db, username=f"user_{i}", email=f"user_{i}@example.com"
|
|
)
|
|
users.append(user)
|
|
|
|
db.commit()
|
|
return users
|
|
except Exception:
|
|
db.rollback()
|
|
raise
|
|
|
|
|
|
def example_update():
|
|
"""Example of updating a record."""
|
|
with get_db() as db:
|
|
# Find user and update
|
|
user = db.query(User).filter(User.username == "john_doe").first()
|
|
if user:
|
|
user.update(db, email="john.doe@newdomain.com", age=31)
|
|
db.commit()
|
|
return user
|
|
|
|
|
|
def example_soft_delete():
|
|
"""Example of soft deleting a record."""
|
|
with get_db() as db:
|
|
user = db.query(User).filter(User.username == "john_doe").first()
|
|
if user:
|
|
# This will set deleted=True instead of actually deleting the record
|
|
user.update(db, deleted=True)
|
|
db.commit()
|
|
|
|
|
|
def example_query():
|
|
"""Example of querying records."""
|
|
with get_db() as db:
|
|
# Get active (non-deleted) users
|
|
active_users = (
|
|
db.query(User)
|
|
.filter(User.active == True, User.deleted == False, User.age >= 18)
|
|
.order_by(User.created_at.desc())
|
|
.all()
|
|
)
|
|
return active_users
|
|
|
|
|
|
def example_complex_transaction():
|
|
"""Example of a complex transaction with multiple operations."""
|
|
with get_db() as db:
|
|
try:
|
|
# Multiple operations in single transaction
|
|
user = User.find_or_create(db, username="new_user", email="new@example.com")
|
|
|
|
# Update existing user
|
|
other_user = db.query(User).filter(User.username == "old_user").first()
|
|
if other_user:
|
|
other_user.update(db, email="updated@example.com")
|
|
|
|
# Soft delete another user
|
|
deleted_user = db.query(User).filter(User.username == "to_delete").first()
|
|
if deleted_user:
|
|
deleted_user.update(db, deleted=True)
|
|
|
|
# Commit all changes at once
|
|
db.commit()
|
|
|
|
except Exception:
|
|
# Rollback all changes if any operation fails
|
|
db.rollback()
|
|
raise
|
|
|
|
|
|
def example_serialization():
|
|
"""Example of serializing records to dictionaries."""
|
|
with get_db() as db:
|
|
user = db.query(User).first()
|
|
if user:
|
|
# Get all fields except specified ones
|
|
dict_with_excludes = user.get_dict(exclude=["created_at", "updated_at"])
|
|
|
|
# Get only specified fields
|
|
dict_with_includes = user.get_dict(include=["id", "username", "email"])
|
|
|
|
return {"excluded": dict_with_excludes, "included": dict_with_includes}
|
|
|
|
|
|
def example_confirmation():
|
|
"""Example of confirming a record."""
|
|
with get_db() as db:
|
|
user = db.query(User).filter(User.username == "pending_user").first()
|
|
if user:
|
|
# Only update confirmation status
|
|
user.update(db, is_confirmed=True)
|
|
db.commit()
|
|
return user
|
|
|
|
|
|
# Example of error handling
|
|
def example_error_handling():
|
|
"""Example of proper error handling."""
|
|
with get_db() as db:
|
|
try:
|
|
# Attempt to create user
|
|
user = User.find_or_create(
|
|
db,
|
|
username="existing_user", # This might cause unique constraint violation
|
|
email="exists@example.com",
|
|
)
|
|
db.commit()
|
|
return {"status": "success", "user": user.get_dict()}
|
|
|
|
except Exception as e:
|
|
db.rollback()
|
|
return {
|
|
"status": "error",
|
|
"message": str(e),
|
|
"error_type": e.__class__.__name__,
|
|
}
|
|
|
|
|
|
# Example of working with dates
|
|
def example_date_handling():
|
|
"""Example of working with dates and expiry."""
|
|
with get_db() as db:
|
|
# Find records valid at current time
|
|
current_users = (
|
|
db.query(User)
|
|
.filter(
|
|
User.expiry_starts <= datetime.utcnow(),
|
|
User.expiry_ends > datetime.utcnow(),
|
|
)
|
|
.all()
|
|
)
|
|
|
|
# Set expiry for a user
|
|
user = db.query(User).first()
|
|
if user:
|
|
user.update(db, expiry_ends=datetime(2024, 12, 31, 23, 59, 59))
|
|
db.commit()
|
|
|
|
return current_users
|