我使用 Alembic、sqlalchemy、Postgresql。 创建迁移 ' alembic revision --autogenerate -m "First"' 时，alembic 每次都会重新创建表。如何重新配置它以使其仅进行更改？
env.py
from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
# 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)
from app.models.map import Base
# 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"},
include_schemas=True
)
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()
在配置中添加 `include_schemas=True ' 没有帮助。
这就是班级的样子。
class Person(Base):
"""Person in department class."""
__tablename__ = "person"
__table_args__ = {"schema": "core"}
id = Column(TEXT, primary_key=True, nullable=False)
status = Column(TEXT, nullable=False)
created_utc = Column(TIMESTAMP(timezone=False), nullable=False)
updated_utc = Column(TIMESTAMP(timezone=False), nullable=False)
subject_id = Column(TEXT, nullable=True)
lastname = Column(TEXT, nullable=True)
firstname = Column(TEXT, nullable=True)
middlename = Column(TEXT, nullable=True)
birthday = Column(DATE, nullable=True)
awards = relationship("Awards", back_populates="in_person")
def __repr__(self):
return "{} {} {}".format(self.lastname, self.firstname, self.middlename)
在不同的方案中有几个这样的类。