Odoo Deployment and Upgrades – Production Best Practices

{
    'name': 'Library Management',
    'version': '19.0.1.0.1',  # Odoo 19, module version 1.0.1
    # When you change module_version (last 2 numbers),
    # Odoo will run migration scripts on next -u
}

# migrations/19.0.1.0.1/pre_migrate.py
# Runs BEFORE new field definitions are applied
def migrate(cr, version):
    """Rename column before ORM recreates it."""
    if not version:
        return  # first install, skip
    cr.execute("""
        ALTER TABLE library_book
        RENAME COLUMN old_field_name TO new_field_name
    """)


# migrations/19.0.1.0.1/post_migrate.py
# Runs AFTER new field definitions and XML data loading
def migrate(cr, version):
    """Backfill new column from existing data."""
    if not version:
        return
    cr.execute("""
        UPDATE library_book
        SET full_title = title || ' by ' || author
        WHERE full_title IS NULL
    """)

# __manifest__.py
{
    'name': 'Library Management',
    'version': '19.0.1.0.0',
    'pre_init_hook': 'pre_init_hook',
    'post_init_hook': 'post_init_hook',
    'post_load': 'post_load',
}

# __init__.py
def pre_init_hook(env):
    """Runs before module tables are created.
    Use for checks or pre-setup only — tables don't exist yet.
    """
    pass

def post_init_hook(env):
    """Runs after first install only.
    Tables exist; create default records here.
    """
    env['library.category'].create({'name': 'General'})

def post_load():
    """Runs after module code is loaded but before install.
    Use for monkey-patching third-party libraries.
    """
    pass