问Python Flask: sqlalchemy.exc.ArgumentError:无法从字符串'sqlite‘解析rfc1738 URL

EN

from flask import Flask, render_template, request, redirect, url_for
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime




 
app = Flask(__name__)

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite: ////C:/Users/admin/Desktop/Blog_Project/blog.db'

db = SQLAlchemy(app)

class Blogpost(db.Model):

    id = db.Column(db.Integer, primary_key = True)
    title = db.Column(db.String(50))
    subtitle = db.Column(db.String(50))
    author = db.Column(db.String(20))
    date_posted = db.Column(db.DateTime)
    content = db.Column(db.Text)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/about')
def about():
    return render_template('about.html')
    

@app.route('/post')
def post():
    return render_template('post.html')


@app.route('/contact')
def contact():
    return render_template('contact.html')


@app.route('/prova')
def prova():
    return render_template('prova.html')


@app.route('/add')
def add():
    return render_template('add.html')

@app.route('/addpost', methods=['POST'])
def addpost():
    title = request.form['title']
    subtitle = request.form['subtitle']
    author = request.form["author"]
    content = request.form['content']

    post = Blogpost(title=title, subtitle=subtitle, author=author, content=content, date_posted=datetime.now())

    db.session.add(post)
    db.session.commit()

    return redirect(url_for('index'))

if __name__ == "__main__":
    app.run(debug = True)

sqlalchemy.exc.ArgumentError

sqlalchemy.exc.ArgumentError: Could not parse rfc1738 URL from string 'sqlite: ////C:/Users/admin/Desktop/Blog_Project/blog.db'