Python使用Alembic框架进行数据库版本管理
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安装
pip install alembic
初始化
alembic init alembic
修改配置alembic.ini
sqlalchemy.url = driver://user:pass@localhost/dbname
修改env.py
import
sys
from logging.config import fileConfig
from os.path import abspath, dirname
from alembic import context
from sqlalchemy import engine_from_config
from sqlalchemy import pool
sys.path.append(dirname(dirname(abspath(__file__))))
from models.models import Base
# 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()
创建第一个版本
alembic revision --autogenerate -m "init"
修改模型
alembic revision --autogenerate -m "update"
升级
alembic upgrade head #每次要创建新的版本，需要执行数据库升级到新版本的命令，才能继续更新版本
降级
alembic downgrade 版本号
原文：https://www.cnblogs.com/john-xiong/p/13338290.html
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