从Java更新sqlite数据库

Question

I am trying to update a sqlite db from javafx. I perform the following query to my database in order to update it:

try 
  {
  int saveSpeed = gui.saveSpeedInt - gui.saveSpeedTimer;
  String query2;
  if(gui.textAnswerQ.equals(gui.saveAnswer.getText()) || gui.textAnswerToFQ.equals(gui.saveAnswer.getText()) || gui.SanswerTextField.getText().equals(gui.saveAnswer.getText())){

    String answer = "1";
    query2 = "update StudentsQuestions set Time = '"+saveSpeed+"' set Answer = '"+answer+"' where UserName = '"+gui.saveUser.getText()+"' and Question = '"+gui.question.getText()+"'";                 
  }
  else{
    String answer = "0";
    query2 = "update StudentsQuestions set Time = '"+saveSpeed+"' set Answer = '"+answer+"' where UserName = '"+gui.saveUser.getText()+"' and Question = '"+gui.question.getText()+"'";
  }

  PreparedStatement pst2 = gui.connectionUsers.prepareStatement(query2);
  pst2.execute();
  pst2.close();
 }

When I performed the updating all the time the Answer field seems to be empty. Am I doing something wrong here? Aswer is a field from the StudentsQuestions table which type is INTEGER and its schema "Answer INTEGER".

EDIT: Indeed I figure out that I cant put two sets inside the same query. However I am not aware how can I seperate my query into a prepared statement. Any help?

Answer 1

Creating prepared statements is the way to go. I would fix up your code as such (the main error was not having a comma and using set twice in the sql statement):

try 
  {
  int saveSpeed = gui.saveSpeedInt - gui.saveSpeedTimer;
  String query2;
  int answer = 1;
  if(gui.textAnswerQ.equals(gui.saveAnswer.getText()) || gui.textAnswerToFQ.equals(gui.saveAnswer.getText()) || gui.SanswerTextField.getText().equals(gui.saveAnswer.getText())){
    answer = 1;
  }
  else{
    answer = 0;
  }
  query2 = "update StudentsQuestions set Time = ?, Answer = ? where UserName = ? and Question = ?";
  PreparedStatement pst2 = gui.connectionUsers.prepareStatement(query2);
  pst2.setInt(1, saveSpeed);
  pst2.setInt(2, answer);
  pst2.setString(3, gui.saveUser.getText());
  pst2.setString(4, gui.question.getText());
  pst2.execute();
  pst2.close();
 }

for more info see this: Using SQLite Prepared statements basics