带有MySQL INSERT参数的C＃

Question

Good day to all, I'm using Visual C# 2010 and MySQL Version 5.1.48-community. I hope you can help me with this code. I don't find it working on me. What am I missing?

string connString = ConfigurationManager.ConnectionStrings["default"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connString);
conn.Open();
MySqlCommand comm = conn.CreateCommand();
comm.CommandText = "INSERT INTO room(person,address) VALUES(@person, @address)";
comm.Parameters.Add("@person", "Myname");
comm.Parameters.Add("@address", "Myaddress");
comm.ExecuteNonQuery();
conn.Close();

And when I try to compile it. It says:

Person column cannot be null

EDITED:

But when I try this code.

comm.CommandText = "INSERT INTO room(person,address) VALUES('Myname', 'Myaddress')";

But this code is prone to sql injection attack but it works, doesn't gives me an error.

EDITED:

I tried to use this. I found it here so I thought It would work but gives me this error

Index (zero based) must be greater than or equal to zero and less than the size of the argument list.

Any idea?

    string a = "myname";
    MySqlCommand cmd = new MySqlCommand();
    cmd.Connection = conn;
    cmd.CommandText = "INSERT INTO room(person,address) VALUES(?,?)";
    //cmd.Prepare();

    cmd.Parameters.Add("person", MySqlDbType.VarChar).Value = a;
    cmd.Parameters.Add("address", MySqlDbType.VarChar).Value = "myaddress";
    cmd.ExecuteNonQuery(); // HERE I GOT AN EXCEPTION IN THIS LINE

Any help would be much appreciated.

EDITED: SOLVED I used this code:

cmd.CommandText = "INSERT INTO room(person,address) VALUES(?person,?address)";
cmd.Parameters.Add("?person", MySqlDbType.VarChar).Value = "myname";
cmd.Parameters.Add("?address", MySqlDbType.VarChar).Value = "myaddress";
cmd.ExecuteNonQuery();

Thanks SO!

Answer 1

You may use AddWithValue method like:

string connString = ConfigurationManager.ConnectionStrings["default"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connString);
conn.Open();
MySqlCommand comm = conn.CreateCommand();
comm.CommandText = "INSERT INTO room(person,address) VALUES(@person, @address)";
comm.Parameters.AddWithValue("@person", "Myname");
comm.Parameters.AddWithValue("@address", "Myaddress");
comm.ExecuteNonQuery();
conn.Close();

OR

Try with ? instead of @ , like:

string connString = ConfigurationManager.ConnectionStrings["default"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connString);
conn.Open();
MySqlCommand comm = conn.CreateCommand();
comm.CommandText = "INSERT INTO room(person,address) VALUES(?person, ?address)";
comm.Parameters.Add("?person", "Myname");
comm.Parameters.Add("?address", "Myaddress");
comm.ExecuteNonQuery();
conn.Close();

Hope it helps...

Answer 2

Use the AddWithValue method:

comm.Parameters.AddWithValue("@person", "Myname");
comm.Parameters.AddWithValue("@address", "Myaddress");

Answer 3

I had the same issue -- Finally tried the ? sigil instead of @, and it worked.

According to the docs:

Note. Prior versions of the provider used the '@' symbol to mark parameters in SQL. This is incompatible with MySQL user variables, so the provider now uses the '?' symbol to locate parameters in SQL. To support older code, you can set 'old syntax=yes' on your connection string. If you do this, please be aware that an exception will not be throw if you fail to define a parameter that you intended to use in your SQL.

Really? Why don't you just throw an exception if someone tries to use the so called old syntax? A few hours down the drain for a 20 line program...

MySQL::MySQLCommand

Answer 4

Three things: use the using statement, use AddWithValue and prefix parameters with ? and add Allow User Variables=True to the connection string.

 string connString = ConfigurationManager.ConnectionStrings["default"].ConnectionString;
 using (var conn = new MySqlConnection(connString))
 {
      conn.Open();
      var comm = conn.CreateCommand();
      comm.CommandText = "INSERT INTO room(person,address) VALUES(@person, @address)";
      comm.Parameters.AddWithValue("?person", "Myname");
      comm.Parameters.AddWithValue("?address", "Myaddress");
      comm.ExecuteNonQuery();
  }

Also see http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.parameters.aspx for more information about the command usage, and http://dev.mysql.com/doc/refman/5.1/en/connector-net-connection-options.html for information about the Allow User Variables option ( only supported in version 5.2.2 and above ).

Answer 5

I was facing very similar problem while trying to insert data using mysql-connector-net-5.1.7-noinstall and Visual Studio(2015) in Windows Form Application. I am not a C# guru. So, it takes around 2 hours to resolve everything.

The following code works lately:

string connetionString = null;
connetionString = "server=localhost;database=device_db;uid=root;pwd=123;";

using (MySqlConnection cn = new MySqlConnection(connetionString))
{
    try
    {
        string query = "INSERT INTO test_table(user_id, user_name) VALUES (?user_id,?user_name);";
        cn.Open();
        using (MySqlCommand cmd = new MySqlCommand(query, cn))
        {
            cmd.Parameters.Add("?user_id", MySqlDbType.Int32).Value = 123;
            cmd.Parameters.Add("?user_name", MySqlDbType.VarChar).Value = "Test username";
            cmd.ExecuteNonQuery();
        }
    }
    catch (MySqlException ex)
    {
        MessageBox.Show("Error in adding mysql row. Error: "+ex.Message);
    }
}

Answer 6

comm.Parameters.Add("person", "Myname");

Answer 7

What I did is like this.

String person;
String address;
person = your value;
address =your value;
string connString = ConfigurationManager.ConnectionStrings["default"].ConnectionString;
    MySqlConnection conn = new MySqlConnection(connString);
    conn.Open();
    MySqlCommand comm = conn.CreateCommand();
    comm.CommandText = "INSERT INTO room(person,address) VALUES('"+person+"','"+address+"')";
    comm.ExecuteNonQuery();
    conn.Close();

Answer 8

Try adjusting the code at "SqlDbType" to match your DB type if necessary and use this code:

comm.Parameters.Add("@person",SqlDbType.VarChar).Value=MyName;

or:

comm.Parameters.AddWithValue("@person", Myname);

That should work but remember with Command.Parameters.Add(), you can define the specific SqlDbType and with Command.Parameters.AddWithValue(), it will try get the SqlDbType based on parameter value implicitly which can break sometimes if it can not implicitly convert the datatype.

Hope this helps.

Answer 9

try this it is working

 MySqlCommand dbcmd = _conn.CreateCommand();
    dbcmd.CommandText = sqlCommandString;
    dbcmd.ExecuteNonQuery();
    long imageId = dbcmd.LastInsertedId;