alembic_env_example.py

import sys
from pathlib import Path
from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

# Add src directory to path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

# Import models
from src.database.connection import Base
from src.database.models.user import User  
from src.database.models.item import Item
from src.database.models.transaction import Transaction

# Alembic Config object
config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata

def run_migrations_offline() -> None:
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        # Prevent table deletion
        compare_type=True,
        compare_server_default=True,
        render_as_batch=True
    )

    with context.begin_transaction():
        context.run_migrations()

def run_migrations_online() -> None:
    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            # Prevent table deletion
            compare_type=True, 
            compare_server_default=True,
            render_as_batch=True
        )

        with context.begin_transaction():
            context.run_migrations()

if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()