如何在flask-SQLAlchemy从数据库删除记录吗?

Question

如何从Flask SQLAlchemy存储的数据库中删除记录?我这样做了,它仍然显示一个错误:

sqlalchemy.exc.InvalidRequestError: Instance '<users at 0x1d6436a3be0>' is not persisted

这是数据库名称:

db = SQLAlchemy(app)
class users(db.Model):
_id = db.Column("id", db.Integer, primary_key=True)
name = db.Column("name", db.String(100))
email = db.Column("email", db.String(100))

def __init__(self, name, email):
self.name = name
self.email = email

这是我使用的方法:

@app.route("/view", methods=["POST", "GET"])
def view():
if "user" in session:
user = session["user"]

if request.method == "POST":
user = request.form["nm"]
session["user"] = user
found_user = users.query.filter_by(name=user).first()
email = found_user.email
if found_user:
usr = users(user, email)
db.session.delete(usr)
db.session.commit()
flash("An Account has been Deleted!")
else :
flash("Name is not found")
else:
return render_template("view.html", values=users.query.all())
else:
flash("Please Login First")
return redirect(url_for("login"))

Answer 1

您正在尝试删除一个新的user实例。用

创建的

usr = users(user, email)

由于user, email不是主键，所以这是一个不同于您试图删除的用户的用户实例。您应该删除found_user。如:

if found_user:
db.session.delete(found_user)
db.session.commit()
flash("An Account has been Deleted!")