How to query a database after render_template

@app.route('/')
def index():
  content = """
     teste
   """
  user = "Hero"
  return render_template('index.html', **locals())

def index() :
    return render_template('index.html', obj = "object", data = "a223jsd" );

parentfolder
  templates
     home.html
     about.html
  flask_blog.py \\this is the file that contains the route declarations

from flask import Response

if request.method == "POST":
    Date = request.form.get("Date")
    print(Date)
    Appointments=["This should show up."]
    return Response(json.dumps(Appointments), mimetype='application/json')
else:
    return render_template("PatientDashboard.html", Appointments=[])