我有下面的Django模型，其中managed=False，现在我需要将其更改为managed=True，并添加属性选择版本1的char字段

class TblHoldings(models.Model):
    item_code = models.CharField(unique=True, max_length=5)
    product_name = models.CharField(max_length=45)
    service_provider = models.ForeignKey(TblHoldingsServiceProviders,on_delete=models.CASCADE, related_name='service_provider',db_column='service_provider')
    account_details = models.CharField(max_length=100)
    purchase_cost = models.IntegerField()
    current_value = models.IntegerField()
    power_of = models.CharField(max_length=45, blank=True, null=True)
    purchase_date = models.DateTimeField(blank=True, null=True)
    updated_at = models.DateTimeField(blank=True, null=True)
    created_at = models.DateTimeField(blank=True, null=True)

    def __str__(self):
        return self.product_name + ' at ' + self.service_provider.provider_name

    class Meta:
        verbose_name = 'Holding'
        verbose_name_plural = 'Holdings'
        managed = False
        db_table = 'tbl_holdings'

版本2

FIN_GOAL_TERM =(
    ('L', 'Long Term 7+ years'),
    ('M', 'Medium Term 3-7 years'),
    ('S', 'Short Term <2 years'),
)
class TblHoldings(models.Model):
    item_code = models.CharField(unique=True, max_length=5)
    product_name = models.CharField(max_length=45)
    service_provider = models.ForeignKey(TblHoldingsServiceProviders,on_delete=models.CASCADE, related_name='service_provider',db_column='service_provider')
    account_details = models.CharField(max_length=100)
    purchase_cost = models.IntegerField()
    current_value = models.IntegerField()
    power_of = models.CharField(max_length=45, blank=True, null=True)
    purchase_date = models.DateTimeField(blank=True, null=True)
    goal_term = models.CharField(max_length=40, choices=FIN_GOAL_TERM)
    updated_at = models.DateTimeField(blank=True, null=True)
    created_at = models.DateTimeField(blank=True, null=True)

    def __str__(self):
        return self.product_name + ' at ' + self.service_provider.provider_name

    class Meta:
        verbose_name = 'Holding'
        verbose_name_plural = 'Holdings'
        managed = True
        db_table = 'tbl_holdings'

现在我得到了下面的错误运行使迁移，有人可以建议如何解决这个问题吗？？

file"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/base/schema.py"，第447行，add_fieldself.execute（sql，params）File"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/base/schema.py"，第137行，在执行cursor.execute（sql， params）File"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/utils.py"，第99行，在执行返回超级（）。执行（sql， params）File"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/utils.py"，第67行，在执行返回自己。_execute_with_wrappers（sql，参数，许多=假，执行器=自己。_execute）File"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/utils.py"，第76行，在_execute_with_wrappers返回执行器（sql，参数，许多，上下文）文件"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/utils.py"，第84行，_execute返回self.cursor.execute（sql，参数）文件"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/utils.py"，第89行，在退出提高dj_exc_value.with_traceback（回溯）从exc_value文件"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/utils.py"，第84行，_execute返回self.cursor.execute（sql，Params）File"/root/appstaq_fin/venv/lib/python3.6/site-包/django/db/后端/mysql/base.py"，第71行，在执行返回self.cursor.execute（查询，args）File"/root/appstaq_fin/venv/lib/python3.6/site-包/MySQLdb/cursors.py"，_query（查询）File"/root/appstaq_fin/venv/lib/python3.6/site-包/MySQLdb/cursors.py"，第315行，_querydb.query（q）File"/root/appstaq_fin/venv/lib/python3.6/site-包/MySQLdb/connections.py"，第231行，在查询_mysql.connection.query（自我，查询）django. db. utils中。操作错误：（1060，重复的列名称'power_of'）