取出唯一需求并迁移后，在sqlalchemy中获取唯一约束失败

Question

我在sqlite中创建了一个具有unique=True属性的列名模型。后来我决定放弃这个属性，所以我把它改成unique=False，但是我得到了以下错误，好像我从来没有做过更改一样。在

错误：

IntegrityError: (sqlite3.IntegrityError) UNIQUE constraint failed: group.name [SQL: u'INSERT INTO "group" (name, timestamp, parent_id) VALUES (?, ?, ?)'] [parameters: (u'DOW', None, None)]

旧的模型.py在

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新的模型.py在

class Group(db.Model):
    id=db.Column(db.Integer, primary_key=True)
    name=db.Column(db.String(32), nullable=False, unique=False)
    timestamp=db.Column(db.DateTime)
    permissions=db.relationship('Permission', backref='group')
    roles=db.relationship('Role', backref='group')
    messages=db.relationship('Message', backref='group')

    message_groups=db.relationship('Message_Group', backref='group')
    message_users=db.relationship('Message_User', backref='group')
    parent_id=db.Column(db.Integer, db.ForeignKey('group.id'))
    children=db.relationship('Group', backref=db.backref('parent', remote_side=[id]))
    #users backrefs User

以下是我在更改名称后用于升级数据库的迁移脚本

分贝_迁移.py在

#!flask/bin/python
import imp
from migrate.versioning import api
from app import db
from config import SQLALCHEMY_DATABASE_URI
from config import SQLALCHEMY_MIGRATE_REPO
v = api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
migration = SQLALCHEMY_MIGRATE_REPO + ('/versions/%03d_migration.py' % (v+1))
tmp_module = imp.new_module('old_model')
old_model = api.create_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
exec old_model in tmp_module.__dict__
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI,
                                          SQLALCHEMY_MIGRATE_REPO,
                                          tmp_module.meta, db.metadata)
open(migration, "wt").write(script)
api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
v = api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
print('New migration saved as ' + migration)
print('Current database version: ' + str(v))

分贝_升级.py在

#!flask/bin/python
from migrate.versioning import api
from config import SQLALCHEMY_DATABASE_URI
from config import SQLALCHEMY_MIGRATE_REPO
api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
v = api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
print('Current database version: ' + str(v))

请随意评价我的模型，并提供一些技巧，使之更快。我对sql还是个新手。在