Question

我正在尝试使用SQLAlchemy在表中定义主键。问题是由于以下错误，我无法执行此操作：

ArgumentError: Mapper Mapper|BankAccount|bank_account could not assemble any primary key columns for mapped table 'bank_account'

我的代码就是这个：

from flask import Flask,request,jsonify
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
import os

# init app
app = Flask(__name__) 
basedir = os.path.abspath(os.path.dirname(__file__))

# Database
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + 
os.path.join(basedir,'db.sqlite')

app.config ['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

# init db

db = SQLAlchemy(app)
# init marshmallow
ma = Marshmallow(app)

# class account
class BankAccount(db.Model):
    number_acc: db.Column(db.String(50), primary_key = True)
    owner_acc: db.Column(db.String(50))
    bank: db.Column(db.String(50))
    amount_acc: db.Column(db.Float)

    # constructor of the class
   def __init__(self,number_acc,owner_acc,bank,amount_acc):
       self.number_acc = number_acc
       self.owner_acc = owner_acc
       self.bank = bank
       self.amount_acc = amount_acc

如何在表bank_account中插入主键？

Answer 1

SQLAlchemy Column对象的类型不是annotations，因此必须将它们分配为类属性-请参见"Declaring a Mapping"和"Mapping Table Columns"：

class BankAccount(db.Model):
    number_acc = db.Column(db.String(50), primary_key = True)
    owner_acc = db.Column(db.String(50))
    bank = db.Column(db.String(50))
    amount_acc = db.Column(db.Float)

在当前尝试中，实际上Declarative没有在类构造期间找不到的列，因为列信息隐藏在注释中。

无法定义主键

1 个答案: