Question

从本质上讲，我有一个方法来处理从表中获取的数据，以创建一个新的对象“ZExpert”。ZExpert有参数int id、int domain和double ZExpert。我在我获取数据的表中添加了一列，名为“Z_Expert_Score”

我想把对象的双倍ZExpert分数放在Z_Expert_score列中，在“Customer_Expert_ID”=domain和“Customer_ID”=ID的行中。这是我的尝试

ZExpert[] allZExpert = scrCalc.getzExpertAll();

for(int i = 0; i < allZExpert.length; i++) {
  ZExpert currentZExpert = allZExpert[i]; 
  int id = currentZExpert.getId();
  int domain = currentZExpert.getDomain();
  double ZExpertScore = currentZExpert.getzExpert();

  Statement statement = conn.createStatement();
  statement.executeUpdate ("INSERT INTO CONSUMER_EXPERT_ID 
                             where CONSUMER_EXPERT_ID="+domain+"AND CONSUMER_ID="+id+ "(Z_EXPERT_SCORE) VALUES("+ZExpertScore+")");
}

提前感谢！

Answer 1

您需要使用更新SQL语句，而不是插入。

UPDATE CUSTOMER_TABLE SET Z_EXPERT_SCORE = ? WHERE CONSUMER_EXPERT_ID= ? AND CONSUMER_ID= ?

此外，您应该使用PreparedStatement，而不是将Strings组合在一起创建SQL语句。

ZExpert[] allZExpert = scrCalc.getzExpertAll();

for(int i = 0; i < allZExpert.length; i++) {
  ZExpert currentZExpert = allZExpert[i]; 
  int id = currentZExpert.getId();
  int domain = currentZExpert.getDomain();
  double ZExpertScore = currentZExpert.getzExpert();

  String sql = "UPDATE CUSTOMER_TABLE SET Z_EXPERT_SCORE = ? WHERE CONSUMER_EXPERT_ID= ? AND CONSUMER_ID= ?";
  PreparedStatement statement = con.prepareStatement(sql);
  statement.setDouble(1, zExpertScore);
  statement.setInt(2, domain);
  statement.setInt(3, id);
  statement.executeUpdate();
}

Answer 2

如果您重新扩充已经存在的行，您将希望使用UPDATE语句。

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