[这里,我尝试使用only()从cassandra中仅获取两个字段,但是当我传递字段名称时,这给了我上面的错误,我也尝试了传递[[self,但是没有用。得到这两个字段后,我需要将它们转换成两个数组,以便可以用名称和标记来绘制图形。
这里是代码:from flask import *
from flask_cqlalchemy import CQLAlchemy
app = Flask(__name__)
app.config['CASSANDRA_HOSTS'] = ['127.0.0.1']
app.config['CASSANDRA_KEYSPACE'] = "emp"
db = CQLAlchemy(app)
class Student(db.Model):
uid = db.columns.Integer(primary_key=True)
marks = db.columns.Integer(primary_key=True)
username = db.columns.Text(required=True)
password = db.columns.Text()
@app.route('/meriting')
def show_meritlist():
ob = Student.objects().filter().only(Student.marks, Student.username)
ob = ob.filter(Student.marks >= 65).allow_filtering()
return render_template('merit.html', ml = ob)
db.sync_db()
if __name__ == '__main__':
app.run(debug = True)
only()
仅采用一个应该是可迭代的参数。试试:ob = Student.objects().filter().only((Student.marks, Student.username))