[英]Updating a sqlite database from Java
我正在尝试从javafx更新sqlite数据库。 我对数据库执行以下查询以对其进行更新:
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();
}
当我一直执行更新时,答案字段似乎为空。 我在这里做错什么了吗? “ Aswer”是“ StudentsQuestions”表中的一个字段,类型为INTEGER及其模式“ Answer INTEGER”。
编辑:确实,我发现我不能在同一查询中放入两个集合。 但是,我不知道如何将查询分成准备好的语句。 有什么帮助吗?
创建准备好的语句是方法。 我会这样修复您的代码(主要错误是没有逗号,并且在sql语句中两次使用set):
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();
}
有关更多信息,请参见: 使用SQLite Prepared语句基础
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