Question

请帮我解决同样的问题：我不知道如何通过在mysql中自动生成的id从表中删除数据，我认为这个问题可以在JBDC中使用GENERATED_KEY来解决，总而言之我不是知道，帮我提供如何按表ID删除的信息。

表＆＃39;注意＆＃39;：

CREATE TABLE `note` (
`id` MEDIUMINT NOT NULL AUTO_INCREMENT,
`noteName` VARCHAR(100) NOT NULL ,
`note` VARCHAR(1000) NOT NULL ,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

现在我正在获得价值 - ＆＃39; noteName＆＃39;但它是不正确的我需要为表中的每一行获取id

Statement st = con.createStatement();
ResultSet rs;
ResultSet resultSet;
rs = st.executeQuery("SELECT * FROM note");
while (rs.next()) { 
%>
    <tr>
        <td><input type="checkbox"></td>
        <td id="noteName"><%=rs.getString(1) %></td>
        <td><%=rs.getString(2) %></td>
        <td>time</td>
        <td id="close">
            <a href=deleteData?id=<%=rs.getString(1) %>><button onclick="deleteRow()" type="button" class="close" data-dismiss="modal">&times;</button></a>
        </td>
    </tr>
<% }
    rs.close();
    st.close();
    con.close();
%>

我在这里删除数据：

public class deleteData extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int value = Integer.parseInt(request.getParameter("id"));
    try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/evernoteDB",
                "evernoteDB", "0633739768z");

        String query = "DELETE FROM note WHERE noteName = ?";
        PreparedStatement statement = conn.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
        statement.setInt(1, value);
        statement.executeUpdate();

        response.sendRedirect("/userNotes.jsp");

        conn.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
}

Answer 1

您将能够从表中获取所有数据。

<tr>
    <td><%= rs.getInt("id") %></td> returns id
    <td><%= rs.getString("notename") %></td> returns noteName
    <td><%= rs.getString("note") %></td> returns note
</tr>

并改变

<a href=deleteData?id=<%=rs.getString(1) %>>...</a>

到

<a href=deleteData?id=<%= rs.getInt("id") %>>...</a>

并在servlet中将查询更改为

"DELETE FROM note WHERE id = ?"

如何使用id - generated_key从db中删除数据

1 个答案: