【发布时间】：2018-03-09 19:59:51
【问题描述】：
我在 alembic 中进行了一些迁移，并尝试运行 alembic upgrade head 以更新我的数据库以进行修订，但在某些情况下，我有已经存在的表，因此出现错误：
alembic upgrade head
INFO [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO [alembic.runtime.migration] Will assume transactional DDL.
INFO [alembic.runtime.migration] Running upgrade -> 3137cf88d8c6, create tables
Traceback (most recent call last):
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context
context)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/default.py", line 470, in do_execute
cursor.execute(statement, parameters)
psycopg2.ProgrammingError: relation "City" already exists
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/toweya/.virtualenvs/numus3/bin/alembic", line 11, in <module>
sys.exit(main())
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/config.py", line 479, in main
CommandLine(prog=prog).main(argv=argv)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/config.py", line 473, in main
self.run_cmd(cfg, options)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/config.py", line 456, in run_cmd
**dict((k, getattr(options, k, None)) for k in kwarg)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/command.py", line 254, in upgrade
script.run_env()
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/script/base.py", line 416, in run_env
util.load_python_file(self.dir, 'env.py')
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/util/pyfiles.py", line 93, in load_python_file
module = load_module_py(module_id, path)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/util/compat.py", line 64, in load_module_py
module_id, path).load_module(module_id)
File "<frozen importlib._bootstrap_external>", line 388, in _check_name_wrapper
File "<frozen importlib._bootstrap_external>", line 809, in load_module
File "<frozen importlib._bootstrap_external>", line 668, in load_module
File "<frozen importlib._bootstrap>", line 268, in _load_module_shim
File "<frozen importlib._bootstrap>", line 693, in _load
File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 665, in exec_module
File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
File "numus/env.py", line 68, in <module>
run_migrations_online()
File "numus/env.py", line 63, in run_migrations_online
context.run_migrations()
File "<string>", line 8, in run_migrations
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/runtime/environment.py", line 817, in run_migrations
self.get_context().run_migrations(**kw)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/runtime/migration.py", line 323, in run_migrations
step.migration_fn(**kw)
File "/home/toweya/PycharmProjects/NumusPortal/portal/db_manage/numus/versions/3137cf88d8c6_create_tables.py", line 30, in upgrade
sa.Column('name', sa.String(64), nullable=False),
File "<string>", line 8, in create_table
File "<string>", line 3, in create_table
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/operations/ops.py", line 1106, in create_table
return operations.invoke(op)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/operations/base.py", line 318, in invoke
return fn(self, operation)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/operations/toimpl.py", line 101, in create_table
operations.impl.create_table(table)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/ddl/impl.py", line 194, in create_table
self._exec(schema.CreateTable(table))
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/alembic/ddl/impl.py", line 118, in _exec
return conn.execute(construct, *multiparams, **params)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 945, in execute
return meth(self, multiparams, params)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/sql/ddl.py", line 68, in _execute_on_connection
return connection._execute_ddl(self, multiparams, params)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1002, in _execute_ddl
compiled
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1189, in _execute_context
context)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1393, in _handle_dbapi_exception
exc_info
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=cause)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/util/compat.py", line 186, in reraise
raise value.with_traceback(tb)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context
context)
File "/home/toweya/.virtualenvs/numus3/lib/python3.5/site-packages/sqlalchemy/engine/default.py", line 470, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) relation "City" already exists
[SQL: '\nCREATE TABLE "City" (\n\tid SERIAL NOT NULL, \n\tgeoid INTEGER NOT NULL, \n\tname VARCHAR(64) NOT NULL, \n\tPRIMARY KEY (id), \n\tUNIQUE (geoid)\n)\n\n']
如何忽略现有表？
这意味着类似：如果表存在 - 继续但不中止
【问题讨论】：
-
你迁移的迁移路径是什么？？
-
这不是 alembic，而是在
alembic.ini我指定的。重要吗？ -
检查我的回答迁移脚本在迁移/版本下
标签： python-3.x flask sqlalchemy alembic