Python Flask - 使用外键插入表

Question

在数据库关系方面需要帮助。 我有两张表：资金来源和分配摘要，两者之间有4个属性相同。我使用外键是因为两个表之间存在一对多关系 - 一个资金来源可以有多个分配，但一个分配只能有一个资金来源：

这是我的两张桌子：

class FundingSource(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    complete = db.Column(db.String(10), default=False, nullable=False)
    department = db.Column(db.String(100), nullable=False)
    agency = db.Column(db.String(150), nullable=False)
    funding_source = db.Column(db.String(200), nullable=False)
    bill = db.Column(db.String(10), nullable=False)
    tracker = db.Column(db.String(255), nullable=False)
    allocations = db.relationship('AllocationSummary', backref='allocation', lazy=True) 


class AllocationSummary(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    # complete 
    # agency 
    # funding_source 
    # bill
    state = db.Column(db.String(100), nullable=False)
    recipient = db.Column(db.String(200), nullable=False)
    amount = db.Column(db.Float(), nullable=False)
    funding_source_id = db.Column(db.Integer, db.ForeignKey('funding_source.id'), nullable=False)

    def __init__(self, state, eligible_applicant, recipient, amount):
        self.state = state
        self.eligible_applicant = eligible_applicant
        self.recipient = recipient
        self.amount = amount

在我的分配摘要网页中，我有一个插入新分配的按钮，要求您填写表格字段。

这是我插入带有所需表单字段的新分配的代码：

@main.route("/insert", methods=['POST'])
def insert():
    if request.method == 'POST':
        complete = request.form['complete']
        agency = request.form['agency']
        funding_source = request.form['funding_source']
        bill = request.form['bill']
        state = request.form['state']
        eligible_applicant = request.form['eligible_applicant']
        recipient = request.form['recipient']
        amount = request.form['amount']

        my_alloc = AllocationSummary(state, eligible_applicant, recipient, amount)
        db.session.add(my_alloc)
        db.session.commit()

        return redirect(url_for('alloc_summ'))

我的问题是，如果我需要 FundingSource 表中的这些属性，如何将属性“完整”、“代理”、“funding_source”和“bill”包含到 AllocationSummary() 并添加/提交到数据库?

我想我不明白“funding_source_id = db.Column(db.Integer, db.ForeignKey('funding_source.id'), nullable=False)” 是为了获得共同属性？

基本上，我需要：

my_alloc = AllocationSummary(complete, agency, funding_source, bill, state, qualified_applicant, 收件人, amount )

但我无法访问这些属性，因为它们在 FundingSource 表中，那么如何在插入时将它们推送到数据库？

对不起，如果所有这些都令人困惑，我是新手。

Answer 1

感谢allocations 关系，它是反向引用，您可以通过填充AllocationSummary 对象并将其传递给FundingSource 来完成它。但是，这仅在您从模型中删除 __init__ 函数时才有效。

    ...
    complete = request.form['complete']
    agency = request.form['agency']
    funding_source = request.form['funding_source']
    bill = request.form['bill']
    state = request.form['state']
    eligible_applicant = request.form['eligible_applicant']
    recipient = request.form['recipient']
    amount = request.form['amount']
    my_fund_src = FundingSource(
        complete=complete,
        agency,
        funding_source,
        bill=bill,
        allocations=[
            AllocationSummary(
                state=state,
                eligible_applicant=eligible_applicant,
                recipient=recipient,
                amount=amount
            )
        ]
    )
    db.session.add(my_fund_src)
    db.session.commit()
    ...