Passing parameters to IdbCommand for mySQL database

Question

I am trying to do something relatively simple using IdbCommand to execute an insert query.

Here's the code:

using (IDbConnection conn = DbHelper.GetConnection(DbConnString))
        using (IDbCommand com = conn.CreateCommand())
        {
            com.CommandType = CommandType.Text;
            com.CommandText =
                String.Format(
                    "INSERT INTO {0} (`Date`, User, Type, `Comment`) VALUES (@Date, @User, @Type, @Comment);",
                    TableName);
            conn.Open();

            var parameterDate = com.CreateParameter();
            parameterDate.ParameterName = "@Date";
            parameterDate.Value = entry.Date;
            parameterDate.DbType = DbType.DateTime;
            com.Parameters.Add(parameterDate);

            var parameterUser = com.CreateParameter();
            parameterUser.ParameterName = "@User";
            parameterUser.Value = entry.User;
            parameterUser.DbType = DbType.String;
            com.Parameters.Add(parameterUser);

            var parameterLogType = com.CreateParameter();
            parameterLogType.ParameterName = "@Type";
            parameterLogType.Value = entry.Type;
            parameterLogType.DbType = DbType.Int32;
            com.Parameters.Add(parameterLogType);

            var parameterComment = com.CreateParameter();
            parameterComment.ParameterName = "@Comment";
            parameterComment.Value = entry.Comment;
            parameterComment.DbType = DbType.String;
            com.Parameters.Add(parameterComment);

            com.ExecuteNonQuery();

But I keep getting a MySqlException with the message "Column 'Date' cannot be null".

All my selects work fine, it's just this insert that has a problem and I can't see an obvious problem with it.

The parameter is populated with a valid DateTime during runtime. I thought it might be related to the fact that Date is a reserved word and needs backquotes, but that's what online tutorials recommend.

Any ideas?

Answer 1

Found it!

For some reason instead of @, it needs ?

So the working code is:

        using (IDbConnection conn = DbHelper.GetConnection(DbConnString))
        using (IDbCommand com = conn.CreateCommand())
        {
            com.CommandType = CommandType.Text;
            com.CommandText =
                String.Format(
                    "INSERT INTO {0} (`Date`, User, Type, `Comment`) VALUES (?Date, ?User, ?Type, ?Comment);",
                    TableName);
            conn.Open();

            var parameterDate = com.CreateParameter();
            parameterDate.ParameterName = "?Date";
            parameterDate.Value = entry.Date;
            parameterDate.DbType = DbType.DateTime;
            com.Parameters.Add(parameterDate);

            var parameterUser = com.CreateParameter();
            parameterUser.ParameterName = "?User";
            parameterUser.Value = entry.User;
            parameterUser.DbType = DbType.String;
            com.Parameters.Add(parameterUser);

            var parameterLogType = com.CreateParameter();
            parameterLogType.ParameterName = "?Type";
            parameterLogType.Value = entry.Type;
            parameterLogType.DbType = DbType.Int32;
            com.Parameters.Add(parameterLogType);

            var parameterComment = com.CreateParameter();
            parameterComment.ParameterName = "?Comment";
            parameterComment.Value = entry.Comment;
            parameterComment.DbType = DbType.String;
            com.Parameters.Add(parameterComment);

            com.ExecuteNonQuery();

        }