Я пытаюсь перейти на Alembi c.
Env.py:
from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
import sys
import os
sys.path.insert(0, os.getcwd())
print(sys.path)
from appli.Base import Base
print(Base.metadata.sorted_tables)
# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config
# Interpret the config file for Python logging.
# This line sets up loggers basically.
fileConfig(config.config_file_name)
# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = Base.metadata
# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.
def run_migrations_offline():
"""Run migrations in 'offline' mode.
This configures the context with just a URL
and not an Engine, though an Engine is acceptable
here as well. By skipping the Engine creation
we don't even need a DBAPI to be available.
Calls to context.execute() here emit the given string to the
script output.
"""
url = config.get_main_option("sqlalchemy.url")
context.configure(
url=url,
target_metadata=target_metadata,
literal_binds=True,
dialect_opts={"paramstyle": "named"},
)
with context.begin_transaction():
context.run_migrations()
def run_migrations_online():
"""Run migrations in 'online' mode.
In this scenario we need to create an Engine
and associate a connection with the context.
"""
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
)
with context.begin_transaction():
context.run_migrations()
if context.is_offline_mode():
run_migrations_offline()
else:
run_migrations_online()
алемби c .ini:
# A generic, single database configuration.
[alembic]
# path to migration scripts
script_location = alembic
# template used to generate migration files
# file_template = %%(rev)s_%%(slug)s
# timezone to use when rendering the date
# within the migration file as well as the filename.
# string value is passed to dateutil.tz.gettz()
# leave blank for localtime
# timezone =
# max length of characters to apply to the
# "slug" field
# truncate_slug_length = 40
# set to 'true' to run the environment during
# the 'revision' command, regardless of autogenerate
# revision_environment = false
# set to 'true' to allow .pyc and .pyo files without
# a source .py file to be detected as revisions in the
# versions/ directory
# sourceless = false
# version location specification; this defaults
# to alembic/versions. When using multiple version
# directories, initial revisions must be specified with --version-path
# version_locations = %(here)s/bar %(here)s/bat alembic/versions
# the output encoding used when revision files
# are written from script.py.mako
# output_encoding = utf-8
sqlalchemy.url = mysql+pymysql://root@localhost/test_migration
[post_write_hooks]
# post_write_hooks defines scripts or Python functions that are run
# on newly generated revision scripts. See the documentation for further
# detail and examples
# format using "black" - use the console_scripts runner, against the "black" entrypoint
# hooks=black
# black.type=console_scripts
# black.entrypoint=black
# black.options=-l 79
# Logging configuration
[loggers]
keys = root,sqlalchemy,alembic
[handlers]
keys = console
[formatters]
keys = generic
[logger_root]
level = WARN
handlers = console
qualname =
[logger_sqlalchemy]
level = WARN
handlers =
qualname = sqlalchemy.engine
[logger_alembic]
level = INFO
handlers =
qualname = alembic
[handler_console]
class = StreamHandler
args = (sys.stderr,)
level = NOTSET
formatter = generic
[formatter_generic]
format = %(levelname)-5.5s [%(name)s] %(message)s
datefmt = %H:%M:%S
Я инициализирую базу данных первым:
from sqlalchemy import create_engine
import pymysql
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint
Base = declarative_base()
engine = create_engine('mysql+pymysql://root@localhost/test_migration')
#The axis on which the tests are executed
class AXIS(Base):
__tablename__ = 'Axis'
id_axis = Column(Integer, primary_key = True)
name_axis = Column(String(10), nullable=False)
И я получаю это при обновлении версии. Все правильно.
def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.create_table('Axis',
sa.Column('id_axis', sa.Integer(), nullable=False),
sa.Column('name_axis', sa.String(length=10), nullable=False),
sa.PrimaryKeyConstraint('id_axis')
)
# ### end Alembic commands ###
Затем я добавляю столбец с именем test в мою таблицу с именем axis, чтобы проверить миграцию:
#The axis on which the tests are executed
class AXIS(Base):
__tablename__ = 'Axis'
id_axis = Column(Integer, primary_key = True)
name_axis = Column(String(10), nullable=False)
test = Column(String(10), nullable=False)
Далее получаем файл новой версии:
def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.create_table('Axis',
sa.Column('id_axis', sa.Integer(), nullable=False),
sa.Column('name_axis', sa.String(length=10), nullable=False),
sa.Column('test', sa.String(length=10), nullable=False),
sa.PrimaryKeyConstraint('id_axis')
)
op.drop_table('axis')
# ### end Alembic commands ###
Но я заметил, что alembi c сначала попытался создать таблицы (уже существующие), а затем попытался удалить их. Чтобы обновление работало, вы должны переместить дроп перед созданием.
Почему дроп после создания? Если это нормально, пожалуйста, объясните мне. Если это не нормально, что может быть источником моей ошибки?
Спасибо за вашу помощь!