VDS Technologies

You have to use the AspMap.DataSource class instead of data tables to add a relate from a map file to a database table. There is the ChartMapApp sample in AspMap 4.7:

AspMap.Layer layer = map.AddLayer(MapPath("states.shp"));
AspMap.DataSource dataSource = new AspMap.DataSource();
dataSource.ConnectionString = "Provider=SQLNCLI10;Server=myServerAddress;Database=myDataBase;Trusted_Connection=yes";
dataSource.CommandText = "SELECT * FROM demography";

if (!layer.AddRelate("STATE_ABBR", dataSource, "STATE_ABBR"))
     throw new Exception("Cannot add a relate");

AspMap.ChartRenderer chartRenderer = layer.ChartRenderer;
chartRenderer.Add("POP1990", Color.Red);  // POP1990 is from the SQL Server database
chartRenderer.Add("POP1997", Color.Green); // POP1997 is from the SQL Server database
chartRenderer.ChartType = ChartType.Pie;
chartRenderer.MinPieSize = 40;
chartRenderer.MaxPieSize = 60;            

A proper Select statement should return a column with unique values which will be linked by AddRelate with the same column in the map layer. The Select in the sample above returns a recordset with the STATE_ABBR (state abbreviations) column which uniquely identifies each state. The 'states' layer also has a STATE_ABBR column.

Select Count(..) probably cannot be used, it returns a single record without a column that can be used as the key column.

MySql does not have an OLEDB provider that can be used with AspMap.DataSource.

We are working on support for data tables, it will be available in next releases.