c# - 数据库/数据网格上的插入和更新语法错误

Question

这是我的保存按钮命令。 需要帮助才能让它发挥作用，将得到它来为明天的学校项目辩护。 谢谢! 它用于 Datagridview、access、c#。 我使用 2010VS 和 MS Access 2007。

private void save_Click(object sender, EventArgs e)
    {

        if (adminyes.Checked == true || adminno.Checked == true && textBox1.Text != null && textBox2.Text != null && textBox3.Text != null)
        {
            admin = "Yes";

            if (mode == "a")
            {
                x = 0;
                connect.Close();
                connect.ConnectionString = inventorydb;
                connect.Open();
                sqlcommand.CommandText = "SELECT * FROM Users WHERE Username ='" +textBox2.Text+ "' Or User_ID ='" +textBox1.Text+ "' ";
                sqlcommand.Connection = connect;
                OleDbDataReader reader = sqlcommand.ExecuteReader();
                while (reader.Read())
                {
                    x++;
                }

                if (x != 0)
                {
                    MessageBox.Show("", "",MessageBoxButtons.OK);
                }
                else
                {
                    DialogResult res = MessageBox.Show("Are you sure?", "Save User", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);

                    if (DialogResult.Yes == res)
                    {
                        connect.Close();
                        connect.ConnectionString = inventorydb;
                        connect.Open();
                        sqlcommand.CommandText = "INSERT INTO Users (User_ID, Username, Password, Admin) VALUES ('" + textBox1.Text + "','" + textBox2.Text + "', '" + textBox3.Text + "', '" + admin + "') ";
                        sqlcommand.Connection = connect;
                        reader = sqlcommand.ExecuteReader();
                        MessageBox.Show("Record(s) Saved", "Sample");
                    }

                    reset();
                }
            }
            else if (mode == "e")
            {
                DialogResult res = MessageBox.Show("Are you sure?", "Update User", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);

                if (DialogResult.Yes == res)
                {
                    connect.Close();
                    connect.ConnectionString = inventorydb;
                    connect.Open();
                    sqlcommand.CommandText = "UPDATE Users SET User_ID = '" + textBox1.Text + "',  Username = '" + textBox2.Text + "', Password = '" + textBox3.Text + "',Admin = '" + admin + "' WHERE SerialID = '" + idholder + "'  ";
                    sqlcommand.Connection = connect;
                    OleDbDataReader reader = sqlcommand.ExecuteReader();
                    reader.Read();
                    MessageBox.Show("Record(s) Updated", "Sample");

                }

                reset();
            }
        }
        else 
        {
            MessageBox.Show("", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }

Answer 1

Password 是 Access 中的保留字。在您的 SQL 查询中将其更改为 [Password]。您应该像这样包装所有的列和表。

虽然这只是一个学校项目，但我会提到一些事情:

您的代码容易受到 SQL 注入(inject)攻击。以下是如何为您的插入方法解决此问题的示例:

sqlcommand.CommandText = "INSERT INTO [Users] ([User_ID], [Username], [Password], [Admin]) VALUES (@user_id, @username, @password, @admin)";
sqlcommand.Connection = connect;
sqlcommand.Parameters.AddWithValue("@user_id", textBox1.Text);
sqlcommand.Parameters.AddWithValue("@username", textBox2.Text);
sqlcommand.Parameters.AddWithValue("@password", textBox3.Text);
sqlcommand.Parameters.AddWithValue("@admin", admin);
reader = sqlcommand.ExecuteReader();

此外，密码不应以明文形式存储。查看密码散列和加盐以及如何正确处理它以获取更多信息。