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我有一個包含問題和答案我的webapp仍然插入「」和空值如何解決這個問題?
CREATE TABLE question(
id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
ttype INT NOT NULL,
content VARCHAR(1000) NOT NULL,
a1 VARCHAR(200) NOT NULL,
a2 VARCHAR(200) NOT NULL,
a3 VARCHAR(200) NOT NULL,
a4 VARCHAR(200) NOT NULL,
a5 VARCHAR(200) NOT NULL,
correctAnswer VARCHAR(10)
)
和我使用(MVC JSP的servlet)在數據庫中插入
我addquestion()在DAO類是
public int Addquestion(Question q){
int type = q.getTtype();
String content = q.getContent();
String a1 = q.getA1();
String a2 = q.getA2();
String a3 = q.getA3();
String a4 = q.getA4();
String a5 = q.getA5();
String correctAnswer =q.getCorrectAnswer();
Connection con = null;
PreparedStatement insertQuestion = null;
int result = 0;
try{
con = DBConnection.createConnection();
insertQuestion = con.prepareStatement("insert into question(ttype,content,a1,a2,a3,a4,a5,correctAnswer) VALUES (?,?,?,?,?,?,?,?)");
insertQuestion.setInt(1,type);
insertQuestion.setString(2,content);
insertQuestion.setString(3, a1);
insertQuestion.setString(4, a2);
insertQuestion.setString(5, a3);
insertQuestion.setString(6, a4);
insertQuestion.setString(7, a5);
insertQuestion.setString(8, correctAnswer);
result = insertQuestion.executeUpdate();
}
catch(SQLException e){
e.printStackTrace();
}
return result;
}
MySQL表
問題是我認爲(NOT NULL)足以在(Web App)提交空表單時返回錯誤(result = 0)。但我的數據庫仍然採用空值(或「」)?
(注:我不知道什麼是HTML形式的空當回報我提交null或「」)
非常感謝你