5. DataSet, DataTable and DataAdapter

var ds = new DataSet();
using var da = new SqlDataAdapter("SELECT Id, Name, Price FROM Products", cs);
da.Fill(ds, "Products");                  // opens + closes connection automatically

DataTable t = ds.Tables["Products"]!;
foreach (DataRow row in t.Rows) Console.WriteLine($"{row["Name"]}: {row["Price"]}");

t.Rows[0]["Price"] = 999m;                // RowState = Modified
var cb = new SqlCommandBuilder(da);       // auto-generates INSERT/UPDATE/DELETE (needs a primary key)
da.Update(ds, "Products");                // pushes changes back

DataView view = new(t) { RowFilter = "Price > 1000", Sort = "Price DESC" };