Python Flask MySQL 提交将插入，不会更新

Question

我可以插入，但我不能更新。代码摘录：

app/models.py

class Location(db.Model):
    __tablename__ = "my_locations"
    loc_id = db.Column(db.Integer, primary_key=True)
    loc_name = db.Column(db.String(50), nullable=False)
    loc_detail = db.Column(db.String(50), nullable=True)
    loc_postal_code = db.Column(db.String(10), nullable=False)
    __table_args__ = (db.UniqueConstraint('loc_name', 'loc_detail', name='_location_name_detail_uc'),
            )

app/forms.py

class LocationForm(FlaskForm):
    loc_id = IntegerField('Loc ID')
    loc_name = StringField('Name' , validators=[DataRequired(), Length(min=6, max=50)])
    loc_detail = StringField('Detail', validators=[Length(max=50), Optional()])
    loc_postal_code = StringField('Postal Code', validators=[DataRequired(), Length(min=4, max=10)])
    submit = SubmitField('Submit')

app/routes.py

@app.route('/edit_location/<string:loc_id>', methods=["GET", "POST"])
@login_required
def edit_location(loc_id):
    if not current_user.is_authenticated:
        return redirect(url_for('index'))

    if loc_id == "0":
        # Empty form
        title_sub = "Add"
        form = LocationForm(loc_id=loc_id)
        # form.loc_id = loc_id
    else:
        # Populated form
        title_sub = "Edit"
        location = Location.query.filter_by(loc_id=loc_id).first()

        form = LocationForm(loc_id=location.loc_id, \
                            loc_name=location.loc_name, \
                            loc_detail=location.loc_detail, \
                            loc_postal_code=location.loc_postal_code
                           )

    if request.method == "POST" and form.validate_on_submit():
        try:
            location = Location(loc_id=form.loc_id.data, \
                                loc_name=form.loc_name.data, \
                                loc_detail=form.loc_detail.data, \
                                loc_postal_code=form.loc_postal_code.data
                               )

            logging.info("edit_location(): location:" + str(location.loc_postal_code))
            if location.loc_detail:
                loc_str = location.loc_name + ', ' + location.loc_detail
            else:
                loc_str = location.loc_name

            if loc_id == "0":
                db.session.add(location)
                db.session.commit()
                flash('Location (' + loc_str + ') added.', 'success')
            else:
                db.session.commit()
                flash('Location (' + loc_str + ') updated.', 'success')

            return redirect(url_for('location'))

        except IntegrityError:
            logging.error("edit_location(): Intg Exception occurred", exc_info=True)
            db.session.rollback()
            flash('Location (' + loc_str + ') already exists.', 'error')

        except DatabaseError:
            logging.error("edit_location(): DB Exception occurred", exc_info=True)
            db.session.rollback()
        except Exception as e:
            flash('Error in form, site administrators have been notified. We apologize for the inconvenience.', 'error')
            logging.error("edit_location(): Exception occurred", exc_info=True)

    return render_template('edit_location.html', title=title_sub + " Location", loc_id=loc_id, form=form)

app/templates/edit_location.html

{% extends "main_page.html" %}

{% block content %}
<div class="edit-location">
  <div class="page-header">
      <h2>{% block title %}{{title}}{% endblock %}</h2>
  </div>

  {% from "_formhelpers.html" import render_field %}
  <form method=post name="editLocationForm" action="{{ url_for('edit_location', loc_id=form.loc_id.data) }}">
        {{ form.csrf_token }}
        <input type="hidden" name="loc_id" value="{{ form.loc_id.data }}">
    <table>
        <tr>{{ render_field(form.loc_name) }} </tr>
        <tr>{{ render_field(form.loc_detail) }}</tr>
        <tr>{{ render_field(form.loc_postal_code) }}</tr>
        <tr>
            <td></td>
            <td><small id="locDetail" class="form-text text-muted">e.g.: Rink A, Field #2, West Court</small></td>
              </tr>
        <tr>
            <td></td>
            <td>
        <a href="#" class="btn btn-primary" onClick="document.editLocationForm.submit();" role="button"> <span>&check;</span> Submit</a>
        <a class="btn btn-primary" href="{{ url_for('location') }}" role="button"> <span>&times;</span> Cancel</a>
            </td>
        </tr>
    </table>
    <p>

    </form>
</div>
{% endblock %}

当我使用 edit_locations 插入时，我的 loc_id = 0，并且 MySQL 提交按预期工作。当我更新时，我正在关注 link，例如 /edit_locations/5 或 /edit_locations/293。表单按预期预填充，我更新了 loc_postal_code，但是当我单击提交时，它不会更新后端的记录。我可以在日志中看到新的 loc_postal_code，所以我知道新值存在。

Answer 1

如果您根据我发送的示例代码块编辑您的代码，您想要的问题将得到解决。

form = LocationForm(request.form)
if request.method == "POST" and form.validate_on_submit():
    try:
        if loc_id == "0":
            # Add
            location = Location(loc_id=form.loc_id.data,
                                loc_name=form.loc_name.data,
                                loc_detail=form.loc_detail.data,
                                loc_postal_code=form.loc_postal_code.data)

        else:
            # Update
            location = Location.query.filter(Location.loc_id == loc_id).first()

            location.loc_name = form.loc_name.data
            location.loc_detail = form.loc_detail.data
            location.loc_postal_code = form.loc_postal_code.data

        db.session.add(location)
        db.session.commit()
    except Exception as e:
        # Exceptions
        logging.error("...")

Answer 2

谢谢@user11527247！

这是我最终在 routes.py 中所做的：

@app.route('/edit_location/<int:loc_id>', methods=["GET", "POST"])
@login_required
def edit_location(loc_id):
    if not current_user.is_authenticated:
        return redirect(url_for('index'))

    if request.method == "GET":
        if loc_id == 0:
            # Empty form
            title_sub = "Add"
            form = LocationForm(request.form)
            form.loc_id = loc_id
        else:
            # Populated form
            title_sub = "Edit"
            location = Location.query.filter_by(loc_id=loc_id).first()
            form = LocationForm(loc_id=location.loc_id, \
                            loc_name=location.loc_name, \
                            loc_detail=location.loc_detail, \
                            loc_postal_code=location.loc_postal_code
                           )
    else:
        form = LocationForm(request.form)

    if request.method == "POST" and form.validate_on_submit():
        try:
            if loc_id == 0:
                location = Location(loc_id=form.loc_id.data, \
                                loc_name=form.loc_name.data, \
                                loc_detail=form.loc_detail.data, \
                                loc_postal_code=form.loc_postal_code.data
                               )
            else:
                location = Location.query.filter_by(loc_id=loc_id).first()

                location.loc_id = form.loc_id.data
                location.loc_name = form.loc_name.data
                location.loc_detail = form.loc_detail.data
                location.loc_postal_code = form.loc_postal_code.data

                if location.loc_detail:
                    loc_str = location.loc_name + ', ' + location.loc_detail
                else:
                    loc_str = location.loc_name

            db.session.add(location)
            db.session.commit()

            return redirect(url_for('location'))

        except IntegrityError:
            logging.error("edit_location(): Intg Exception occurred", exc_info=True)
            db.session.rollback()
            flash('Location (' + loc_str + ') already exists.', 'error')

        except DatabaseError:
            logging.error("edit_location(): DB Exception occurred", exc_info=True)
            db.session.rollback()
        except Exception as e:
            flash('Error in form, site administrators have been notified. We apologize for the inconvenience.', 'error')
            logging.error("edit_location(): Exception occurred", exc_info=True)

    return render_template('edit_location.html', title=title_sub + " Location", loc_id=loc_id, form=form)

将参数从 string:loc_id 更改为 int:loc_id，并更新了相关的 if 语句
添加明确的 if request.method == "GET" 以确保您的建议，form = LocationForm(request.form)，在 POST 已填充表单的调用期间没有运行
根据 loc_id == 0 在 POST 中设置位置值，来自位置或表单
最后，包括 db.session.add() 和 db.session.commit()。

再次感谢！

Python Flask MySQL 提交将插入，不会更新

Python Flask MySQL commit will insert, will not update

python

mysql-python

flask

flask-sqlalchemy

flask-wtforms