Flask SQLAlchemy关系使请求非常慢

Question

我正在将Flask SQLAlchemy用于我的项目，并且我意识到我的客户页面非常慢，因为我正在尝试为每个客户获取目标。我的结构看起来像这样。

class Users(db.Model):


    __tablename__ = "users"
   id = db.Column(db.Integer, primary_key=True)
   first_name = db.Column(db.String(200), nullable=False)
   last_name = db.Column(db.String(30), nullable=False)
   created_date = db.Column(db.DateTime,nullable=False,default=datetime.datetime.now())
   email  = db.Column(db.Unicode(50), nullable=False)
   account  = db.Column(db.Unicode(10), nullable=False)
   number  = db.Column(db.String(30), nullable=False)
   user_type  = db.Column(db.String(10), nullable=False, default='ADMIN')
   created_by  = db.Column(db.Unicode(10), nullable=False, default='SYSTEM')
   destinations = db.relationship('Destinations', backref="customer",lazy="dynamic")


class Destinations(db.Model):

    __tablename__ = 'destinations'
    import datetime
    id = db.Column(db.Integer, primary_key = True)
    did = db.Column(db.Text, nullable=False)
    gateway = db.Column(db.Text, nullable=False)
    channel = db.Column(db.Text, nullable=False)
    own = db.Column(db.Text, nullable=False)
    number = db.Column(db.Unicode(50), nullable=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    created_by = db.Column(db.Integer,nullable=False)
    created_date = db.Column(db.DateTime, default=datetime.datetime.now())
    expire_date = db.Column(db.DateTime, nullable=False)
    record = db.Column(db.Integer, nullable=False)
    auth_did = db.Column(db.Integer, nullable=False)
    auth_gw  = db.Column(db.Integer, nullable=False)

在我的所有客户页面中，我会快速列出请求的所有客户，但是当我尝试为每个客户加载所有目的地时，请求会花费大量时间来加载。

{% for customer in customers %}
        <tr>
            <td>{{customer.first_name}}</td>
            <td>{{customer.number}}</td>
            <td>
                {% for destination in customer.destinations %}
                    {{destination.number}}<br />
                {% endfor %}
            </td>

            <td>
                {% for destination in customer.destinations %}
                    {{destination.did}}<br />
                {% endfor %}
            </td>
            <td>
                {% for destination in customer.destinations %}
                    {{destination.own}}<br />
                {% endfor %}
            </td>
            <td>

                {% for destination in customer.destinations %}
                    {{destination.created_date|humandatetime|safe}}<br />
                {% endfor %}
            </td>
            <td>

                {% for destination in customer.destinations %}
                    {% if destination.expire_date %}{{destination.expire_date|humandatetime|safe}}{% endif %}<br />
                {% endfor %}
            </td>
            <td>

                {% for destination in customer.destinations %}
                    {{destination.gateway or ''}}<br />
                {% endfor %}
            </td>
            <td>
                {% for destination in customer.destinations %}
                    {{destination.channel or ''}}<br />
                {% endfor %}
            </td>
            <td>
                {% for destination in customer.destinations %}
                    <a href="/customers/destinations/delete/{{destination.did}}/{{destination.id}}">del</a><br />
                {% endfor %}
            </td>
            <td><input type="hidden" value="{{customer.first_name}} {{customer.last_name}}"></td>
            <td><a id="{{customer.id}}" class="user-delete-icon">delete</a></td>
        </tr>
    {% endfor %}

此功能也是让我所有客户都能获得此功能的

customers = db.session.query(Users).filter_by(user_type='CUST').all()

我认为问题是关系类型懒惰但我无法修复它