如何在JAVA和MYSQL中删除记录（字符串）

我成功地删除了一个整数，但当我尝试将其设置为字符串时，它会显示 “where子句中的未知列itemtodelete，但我的itemtodelete是数据库中声明的字符串，而不是整数它不删除字符串的程度如何？”

下面是我的代码：

 private void DeleteButtonActionPerformed(java.awt.event.ActionEvent evt) {                                            
        int del = (prompt):
        if (del == JOptionPane.YES_OPTION){
        DelCurRec();
        }

    }     


   public void DelCurRec() {

        String id = field.getText();
        String SQL = "DELETE FROM inventory WHERE ItemCode = "+id+" ";

        try {
           Class.forName(connectio);
       }  catch (Exception e) {
           JOptionPane.showMessageDialog(null,""+e.getMessage(),"JDBC Driver Error",JOptionPane.WARNING_MESSAGE);
       }

        Statement stmt = null;
        Connection con = null;

        //Creates connection to database
        try {
            con = DriverManager.getConnection("Connection");
            stmt = con.createStatement();
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null,""+e.getMessage(),"Connection Error",JOptionPane.WARNING_MESSAGE);
        }

        //Execute the SQL statment for deleting records
        try {
            stmt.executeUpdate(SQL);
            //This closes the connection to the database
            con.close();
            //This closes the dialog
            JOptionPane.showMessageDialog(null,"Deleted Succesfully","Delete Successful",JOptionPane.WARNING_MESSAGE);
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null,""+e.getMessage(),"Communication Error",JOptionPane.WARNING_MESSAGE);
        }
    }

尝试更改行：

String SQL = "DELETE FROM inventory WHERE ItemCode = "+id+" ";

到

---

我认为您需要传递

Integer.parseInt（id）

而不是

id

…假设您的

id

是

int
不要使用
语句
而是使用
PreparedStatement
，否则您的应用程序将容易受到SQL注入的攻击。例如，有人输入一个字符串，如：
”；下表库存--“

相应的准备好的状态看起来像：

String SQL = "DELETE FROM inventory WHERE ItemCode = ? ";
PreparedStatement pstmt = null;

// get a connection and then in your try catch for executing your delete...

pstmt = con.prepareStatement(SQL); 
pstmt.setString(1, id);
pstmt.executeUpdate();

String SQL = "DELETE FROM inventory WHERE ItemCode = ? ";
PreparedStatement pstmt = null;

// get a connection and then in your try catch for executing your delete...

pstmt = con.prepareStatement(SQL); 
pstmt.setString(1, id);
pstmt.executeUpdate();