C# Oledb 更新命令
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Oledb Update command
提问by Pyromancer
I make a program that saves and update a data from the database, I can save and read data, I can also update but the problem is, I can't select the "ID"as the index, here is my sample code using "ID"as the index,
我制作了一个从数据库中保存和更新数据的程序，我可以保存和读取数据，我也可以更新但问题是，我不能选择"ID"作为索引，这是我"ID"用作索引的示例代码，
cmd = new OleDbCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE Records SET FirstName = @firstname, LastName = @lastname, Age = @age, Address = @address, Course = @course WHERE [ID] = @id";
cmd.Parameters.AddWithValue("@id", int.Parse(label7.Text));
cmd.Parameters.AddWithValue("@firstname", textBox1.Text);
cmd.Parameters.AddWithValue("@lastname", textBox2.Text);
cmd.Parameters.AddWithValue("@age", textBox3.Text);
cmd.Parameters.AddWithValue("@address", textBox4.Text);
cmd.Parameters.AddWithValue("@course", textBox5.Text);
cmd.Connection = cn;
cn.Open();
cmd.ExecuteNonQuery();
{
MessageBox.Show("Update Success!");
cn.Close();
}
and here is my update code that works, but the index is the "firstname",
这是我的更新代码有效，但索引是"firstname"，
cmd = new OleDbCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE Records SET FirstName = @firstname, LastName = @lastname, Age = @age, Address = @address, Course = @course WHERE FirstName = @firstname";
//cmd.Parameters.AddWithValue("@id", int.Parse(label7.Text));
cmd.Parameters.AddWithValue("@firstname", textBox1.Text);
cmd.Parameters.AddWithValue("@lastname", textBox2.Text);
cmd.Parameters.AddWithValue("@age", textBox3.Text);
cmd.Parameters.AddWithValue("@address", textBox4.Text);
cmd.Parameters.AddWithValue("@course", textBox5.Text);
cmd.Connection = cn;
cn.Open();
cmd.ExecuteNonQuery();
{
MessageBox.Show("Update Success!");
cn.Close();`
}
It works but the problem is I can't update the "FirstName", Is there a way that I can also update the Firstname? or use the "ID"as the index? thanks
它有效，但问题是我无法更新"FirstName"，有没有办法也可以更新名字？或使用"ID"作为索引？谢谢
采纳答案by DRapp
I don't know what database you are going against, however, I don't know if the OleDB is being picky on the ordinal sequence of your parameters. ie: Have you tried putting your "ID" parameter in the last position to match the actual order of the fields of your update command? I don't know if it's throwing it out.
我不知道您要针对哪个数据库，但是，我不知道 OleDB 是否对您的参数顺序有挑剔。即：您是否尝试将“ID”参数放在最后一个位置以匹配更新命令字段的实际顺序？不知道是不是扔了
回答by user4618777
You should add the following code after the last line of ID:
您应该在最后一行之后添加以下代码ID：
cmd = new OleDbCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "UPDATE Records SET FirstName = @firstname, LastName = @lastname, Age = @age, Address = @address, Course = @course WHERE [ID] = @id";
cmd.Parameters.AddWithValue("@firstname", textBox1.Text);
cmd.Parameters.AddWithValue("@lastname", textBox2.Text);
cmd.Parameters.AddWithValue("@age", textBox3.Text);
cmd.Parameters.AddWithValue("@address", textBox4.Text);
cmd.Parameters.AddWithValue("@course", textBox5.Text);
cmd.Parameters.AddWithValue("@id", int.Parse(label7.Text));
cmd.Connection = cn;
cn.Open();
cmd.ExecuteNonQuery(); {
MessageBox.Show("Update Success!");
cn.Close();
}
