增加： user = db.session.add(user) db.session.commit()

查询： User.query.filter(User.username == 'mis1114').first()

修改： user.password = '111111' db.session.commit()

删除： db.session.delete(user) db.session.commit()

from flask import Flask,render_templatefrom flask_sqlalchemy import SQLAlchemyimport configapp = Flask(__name__)app.config.from_object(config)db=SQLAlchemy(app)class User(db.Model):    __tablename__='user'    id=db.Column(db.Integer,primary_key=True,autoincrement=True)    username = db.Column(db.String(20), nullable=False)    password = db.Column(db.String(20), nullable=False)    nickname = db.Column(db.String(50))#db.create_all()#增加数据user=User(username = 'shanshan1',password = '111111')db.session.add(user)db.session.commit()#查询数据user=User.query.filter(user.username == 'shanshan1').first()print(user.id,user.username,user.password)#修改数据user=User.query.filter(user.username == 'shanshan3').first()user.password = '0000'db.session.commit()#删除数据user=User.query.filter(user.username == 'shanshan3').first()db.session.delete(user)db.session.commit()@app.route('/')def index():    return  render_template('shouye.html')@app.route(   '/manhua/')def manhua():    return  render_template('manhua.html')@app.route(  '/login/')def login():    return render_template('denglu.html')@app.route('/register/')def register():    return render_template('zhuce.html')@app.route('/wenda/')def wenda():    return render_template('wenda.html')if __name__ == '__main__':    app.run(debug=True)