Python-sqlalchemy.exc.ArgumentError：无法为映射表组装任何主键列[重复]

Question

我正在使用 Flask + Alembic + Sqlalchemy。我想创建两个表并使用它。首先，我运行 alembic 脚本：

"""add table insurace_bands and insurace_discounts

Revision ID: 39ba7ec3428
Revises: 18468fbedbac
Create Date: 2015-05-12 09:10:05.175513

"""

# revision identifiers, used by Alembic.
revision = '39ba7ec3428'
down_revision = '18468fbedbac'

from alembic import op
import sqlalchemy as sa

def upgrade():

        op.create_table('insurance_bands',

                sa.Column('id', sa.Integer(), nullable=False),

                sa.Column('name', sa.String(length=1024), nullable=False),

                sa.Column('product_price', sa.Numeric(precision=6, scale=2)),

                sa.Column('monthly_price', sa.Numeric(precision=6, scale=2)),

                sa.Column('active', sa.Boolean(), nullable=False, server_default='1'),

                sa.PrimaryKeyConstraint('id')
                )

    op.create_table('insurance_discounts',

                sa.Column('id', sa.Integer(), nullable=False),

                sa.Column('name', sa.String(length=1024), nullable=False),

                sa.Column('min_products', sa.Integer()),

                sa.Column('max_products', sa.Integer()),

                sa.Column('discount', sa.Numeric(precision=6, scale=2)),

                sa.Column('active', sa.Boolean(), nullable=False, server_default='1'),

                sa.PrimaryKeyConstraint('id')
                )

def downgrade():

    op.drop_table(
    'insurance_bands'
    )


    op.drop_table(
    'insurance_discounts'
    )

这个脚本运行正常。然后，我创建了两个这样的模型：

# -*- coding: utf-8 -*-
"""
    admin.insurance_brands.models
    ~~~~~~~~~~~~~~~~~~~~~

    insurance brand models
"""

from ..core import db
from ..helpers import JsonSerializer


class InsuranceBandJsonSerializer(JsonSerializer):
    __json_public__ = ['id', 'name', 'product_price', 'monthly_price', 'active']


class InsuranceBand(InsuranceBandJsonSerializer, db.Model):

    __tablename__ = 'insurance_bands'

    id = db.Column(db.Integer(), primary_key=True),
    name = db.Column(db.Unicode(1024)),
    product_price = db.Column(db.Numeric(precision=6, scale=2)),
    monthly_price = db.Column(db.Numeric(precision=6, scale=2)),
    active = db.Column(db.Boolean, default=True)


class InsuranceDiscountJsonSerializer(JsonSerializer):
    __json_public__ = ['id', 'name', 'min_products', 'max_products', 'active']


class InsuranceDiscount(InsuranceDiscountJsonSerializer, db.Model):

    __tablename__ = 'insurance_discounts'

    id = db.Column(db.Integer(), primary_key=True),
    name = db.Column(db.Unicode(1024)),
    min_products = db.Column(db.Integer()),
    max_products = db.Column(db.Integer()),
    active = db.Column(db.Boolean, default=True)

但是当我运行服务器：python wsgi.py 时，它会抛出错误：

sqlalchemy.exc.ArgumentError: Mapper Mapper|InsuranceBand|insurance_bands 无法为映射表“insurance_bands”组装任何主键列

似乎模型没有主键，但我定义了它。

谁能帮帮我。提前致谢。

Answer 1

在您的课程中，您必须删除) 之后的,

class InsuranceBand(InsuranceBandJsonSerializer, db.Model):

    __tablename__ = 'insurance_bands'

    id = db.Column(db.Integer(), primary_key=True)
    name = db.Column(db.Unicode(1024))
    product_price = db.Column(db.Numeric(precision=6, scale=2))
    monthly_price = db.Column(db.Numeric(precision=6, scale=2))
    active = db.Column(db.Boolean, default=True)