Bug #74958 MySqlDataAdapter passes data to DataTable by reference rather than by value

• Submitted: 21 Nov 2014 11:13
• Modified: 21 May 2020 18:38
• Reporter: Piers Karsenbarg
• Status: Can't repeat
• Category: Connector / NET
• Severity: S2 (Serious)
• Version: 6.9.5.0
• OS: Windows
• CPU Architecture: Any

[21 Nov 2014 11:13] Piers Karsenbarg

Description:
When using MySqlDataAdapter to fill a DataTable (or DataSet), the data only sits in the DataTable for as long as the MySqlDataAdapter is in scope.

How to repeat:
DataTableReader reader;
            using (var connection = new MySqlConnection(_connectionString))
            {
                using (var command = new MySqlCommand())
                {
                    command.CommandType = commandType;
                    command.CommandText = sql;
                    command.Connection = connection;
                    if (parameters != null)
                    {
                        command.Parameters.AddRange(parameters);
                    }
                    using (var adapter = new MySqlDataAdapter())
                    {
                        adapter.SelectCommand = command;
                        using (var dataTable = new DataTable())
                        {
                            adapter.Fill(dataTable);
                            reader = dataTable.Copy().CreateDataReader();
                            // at this point reader contains rows of data
                        }
                    }
                }
            }
            while (reader.Read())
            {
                // at this point the reader is empty
            }

Suggested fix:
When MySqlDataAdapter.Fill() is called, pass the value by value rather than reference.

[21 Nov 2014 12:00] Piers Karsenbarg

After doing a little bit more digging, it seems that the MySqlDataAdapter.Fill() method comes straight from DbDataAdapter that SqlDataAdapter uses, so how come it's passing the data by reference rather than value?

[21 Jan 2015 5:35] Chiranjeevi Battula

Hello Piers Karsenbarg,

Thank you for the bug report.
Verified this behavior on Visual Studio 2013 (C#.Net) with  MySQL Connector/Net 6.9.5.

Thanks,
Chiranjeevi.

[21 May 2020 18:38] Daniel Valdez

Posted by developer:
 
Verified using latest Connector/NET version, 8.0.20, and this behavior is no longer occurring.