Question

我有一个数据库表，根据他们的表现记录学生的分数和评论：

| NAME   | SCORE | REMARKS | 
+--------+-------+---------+
| james  | 150.0 |         | 
| jimmy  | 90.0  |         | 
| josh   | 200.0 |         |

我想根据学生的分数更新“备注”栏目，如果学生分数低于100，备注文字将为“失败”，从100到160：“平均通过”和161至250“通行证”。

我写了这段代码：

String student_score, remark;
double type;
try {
    String sql = "select SCORE from class";
    pst = conn.prepareStatement(sql);
    rs = pst.executeQuery();
    student_score = rs.getString("SCORE");
    type = Double.parseDouble(student_score);
    while (rs.next()) {
        if (type >= 1 && type <= 100) {
            remark = "fail";
            String sql1 = "update class set Remarks='" + remark + "'" + " WHERE SCORE='" + type + "'";
            pst = conn.prepareStatement(sql1);
            pst.execute();
        } else if (type >= 101 && type <= 160) {
            remark = "average pass";
            String sql1 = "update class1 set Remarks='" + remark + "'" + " WHERE SCORE='" + type + "'";
            pst = conn.prepareStatement(sql1);
            pst.execute();
        } else if (type >= 161 && type <= 250) {
            remark = "pass";
            String sql1 = "update class set Reemarks='" + remark + "'" + " WHERE SCORE='" + type + "'";
            pst = conn.prepareStatement(sql1);
            pst.execute();
        }
    }
} catch (SQLException | HeadlessException e) {
    JOptionPane.showMessageDialog(null, e);

但是有了这个，我只填充了第一行，其余的仍然是空的：

| NAME  | SCORE | REMARKS    | 
+-------+-------+------------+
| james | 150.0 |average pass| 
| jimmy | 90.0  |            | 
| josh  |200.0  |            |

Answer 1

移动

student_score = rs.getString("SCORE");
type = Double.parseDouble(student_score);

到while循环

while (rs.next()) {
 student_score = rs.getString("SCORE");
 type = Double.parseDouble(student_score); 
        ...
}

Answer 2

满足您的要求的最简单方法是直接在SQL中完成所有操作：

String sql1 = "update class set Remarks='fail' WHERE SCORE BETWEEN 1 AND 100";
String sql2 = "update class set Remarks='average pass' WHERE SCORE BETWEEN 101 AND 160";
String sql3 = "update class set Remarks='pass' WHERE SCORE BETWEEN 161 AND 250";

// execute the queries

这不是＆＃34;最佳做法＆＃34;这样做，但它相当于你的解决方案，同时更紧凑，更容易重构。

根据学生的分数为学生创建文本备注

2 个答案: