In C# & .NET, can one create a DataView
that includes only a proper subset of the DataColumn
s of a given DataTable
?
In terms of relational algebra, one assigns a RowFilter
in order to perform a "selection" operation (σ). How would one perform a "projection" operation (π)?
You can't do that, but you can create a copy of the table with only the columns you want :
DataView view = new DataView(table);
DataTable table2 = view.ToTable(false, "FirstColumn", "SecondColumn", "ThirdColumn");
Optionally you can return rows that have distinct values for the selected columns :
DataView view = new DataView(table);
DataTable table2 = view.ToTable(true, "FirstColumn", "SecondColumn", "ThirdColumn");