Question

我有以下型号

models.py

class Rules(db.Model):
    name=db.Column(db.String, primary_key=True)
    rule=db.Column(db.Integer, default='0', unique=False)

    def __repr__(self):  # pragma: no cover
        return '<Rules %r>' % (self.name)

如果我尝试在其中存储数据，它声称规则有一个独特的要求。我事件竟然明确声明unique = False，但它仍然声称它必须是唯一的以下错误

sqlalchemy.exc.IntegrityError: (sqlite3.IntegrityError) UNIQUE constraint        failed: rules.rule [SQL: u'INSERT INTO rules (name, rule) VALUES (?, ?)'] [parameters: ('dod_iaa_cyber', '2')]

我多次运行以下脚本尝试迁移它并修复错误无效。

db_migrate.py

#!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))

007_migration.py，从003-007开始的所有迁移都与此相同

from sqlalchemy import *
from migrate import *


from migrate.changeset import schema
pre_meta = MetaData()
post_meta = MetaData()

def upgrade(migrate_engine):
    # Upgrade operations go here. Don't create your own engine; bind
    # migrate_engine to your metadata
    pre_meta.bind = migrate_engine
    post_meta.bind = migrate_engine


def downgrade(migrate_engine):
    # Operations to reverse the above upgrade go here.
    pre_meta.bind = migrate_engine
    post_meta.bind = migrate_engine

002_migration.py，这个与其他人不同，并且将规则作为主键

from sqlalchemy import *
from migrate import *


from migrate.changeset import schema
pre_meta = MetaData()
post_meta = MetaData()
rules = Table('rules', post_meta,
    Column('rule', Integer, primary_key=True, nullable=False),
    Column('name', String(length=45)),
)


def upgrade(migrate_engine):
    # Upgrade operations go here. Don't create your own engine; bind
    # migrate_engine to your metadata
    pre_meta.bind = migrate_engine
    post_meta.bind = migrate_engine
    post_meta.tables['rules'].create()


def downgrade(migrate_engine):
    # Operations to reverse the above upgrade go here.
    pre_meta.bind = migrate_engine
    post_meta.bind = migrate_engine
    post_meta.tables['rules'].drop()

那么为什么新的迁移没有恢复，我将规则从主键更改为只是一个整数，如何才能将其正确转换为未来呢？

Answer 1

你的名字是否独一无二？拥有主键意味着该字段是唯一的。

Answer 2

修复是删除models.py中的表规则然后迁移数据库，从而强制它丢弃。在病房之后，我重新添加规则并再次迁移。这次它识别出Rules.rule不是唯一的密钥并且正确迁移。

感谢帮助人员。我不确定为什么它没有发现我在迁移过程中将规则更改为标准整数，但一切都很顺利。

sqlalchemy声明专栏有其独特的要求

2 个答案: