trove error

2017-07-11 18:34:26.510 15437 ERROR root InternalError: (pymysql.err.InternalError) (1832, u"Cannot change column 'datastore_version_id': used in a foreign key constraint 'instances_ibfk_1'") [SQL: u'\nALTER TABLE instances CHANGE COLUMN datastore_version_id datastore_version_id VARCHAR(36) NOT NULL']
2017-07-11 18:34:26.510 15437 ERROR root
2017-07-11 18:37:18.250 16343 INFO trove.db.sqlalchemy.session [-] Creating SQLAlchemy engine with args: {'pool_recycle': 3600, 'echo':
False}