类似问题
https://www.cnblogs.com/juandx/p/5278800.html
修改models.py后运行db_migrate发生错误：
./db_migrate.py
/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/flask_sqlalchemy/__init__.py:794: FSADeprecationWarning: SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and will be disabled by default in the future. Set it to True or False to suppress this warning.
'SQLALCHEMY_TRACK_MODIFICATIONS adds significant overhead and '
Traceback (most recent call last):
File "./db_migrate.py", line 19, in <module>
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_module.meta, db.metadata)
File "<decorator-gen-13>", line 2, in make_update_script_for_model
File "/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/migrate/versioning/util/__init__.py", line 97, in catch_known_errors
return f(*a, **kw)
File "<decorator-gen-12>", line 2, in make_update_script_for_model
File "/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/migrate/versioning/util/__init__.py", line 167, in with_engine
return f(*a, **kw)
File "/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/migrate/versioning/api.py", line 321, in make_update_script_for_model
engine, oldmodel, model, repository, **opts)
File "/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/migrate/versioning/script/py.py", line 70, in make_update_script_for_model
genmodel.ModelGenerator(diff,engine).genB2AMigration()
File "/home/hy/.virtualenvs/hy-py3/lib/python3.5/site-packages/migrate/versioning/genmodel.py", line 219, in genB2AMigration
for modelCol, databaseCol, modelDecl, databaseDecl in td.columns_different:
ValueError: too many values to unpack (expected 4)
查网上，有数据类型错，有版本匹配错，真实原因不明，但重新指定版本安装并未解决，简单粗暴：
删除xxx.db数据库文件，然后重新构建
运行db_create.py
再运行db_migrate.py
搞定