java如何在数据库中插入一行？

Question

我写这段代码是为了向数据库添加内容，但是，当我尝试运行它时，它不起作用，我一直在寻找方法，但我似乎找不到解决方案，有人能帮我吗

String mySQL ="INSERT INTO Measurement (Level, Time, Date, TankID)"+"VALUES (textField1, currentTime,currentDate,(SELECT TankID FROM Tanks WHERE TankName = '2' AND Site_ID = '1'))";

stmt.executeUpdate(mySQL);

Answer 1

您应该使用PreparedStatement正确设置插入查询的第一个参数，并检查数据库服务器的文档，以使用现有函数获取当前时间和日期

例如，mySQL有函数^{}和^{}

String query = "INSERT INTO Measurement (Level, Time, Date, TankID) "
    + "VALUES (?, CURTIME(), CURDATE(), (SELECT TankID FROM Tanks WHERE TankName = '2' AND Site_ID = '1'))";

try (PreparedStatement statement = connection.prepareStatement(query)) {
    statement.setString(1, textField1); // could be textField1.getText() or textField1.getValue()
    statement.executeUpdate();
}

Answer 2

SQL和prepared语句的格式都不正确。在这里尝试使用INSERT INTO ... SELECT：

String sql = "INSERT INTO Measurement (Level, Time, Date, TankID) ";
sql += "SELECT ?, ?, ?, TankID ";
sql += "FROM Tanks ";
sql += "WHERE TankName = '2' AND Site_ID = '1'";

stmt.setString(1, textField1);
stmt.setString(2, currentTime);  // not sure about the type here
stmt.setString(3, currentDate);  // also not sure about the type

stmt.executeUpdate();

注意，我不确定currentTime和currentDate列的Java和SQL绑定类型。如果不是字符串，则上面的内容必须稍微更改

Answer 3

根据数据库类型更改连接详细信息

Follow this Link for creating JDBC Connection and Inserting data

如果您执行了上述步骤，请忽略这一点