/// <summary>
/// Use LinqToSql to retrieve a collection of objects, then turn that into a
/// distinct set (which might all be done within one SQL statement, explaining
/// the performance)
/// </summary>
private static void FindDistinctCategoriesLinq()
{
var watch = new Stopwatch();
watch.Start();
var db = new SearchResultsContext();
int i = 0;
// figure out how many distinct categories we can find in the entire table:
var distinctCategories = (from sr in db.SearchResults select new {sr.ResultCategoryID}).Distinct();
foreach (var cat in distinctCategories)
{
i += cat.ResultCategoryID;
}
long result = watch.Stop();
ReportResult(watch, result);
}
/// <summary>
/// Get a plain old DataReader, then feed that into the DBContext to retrieve
/// objects, then operate on the collection of objects.
/// </summary>
private static void FindDistinctCategoriesDataReaderLinq()
{
var watch = new Stopwatch();
watch.Start();
using (var conn = new SqlConnection(ConnectionString))
{
conn.Open();
int i = 0;
var cmd = new SqlCommand("SELECT * FROM SearchResults", conn);
using (SqlDataReader dr = cmd.ExecuteReader())
{
var db = new SearchResultsContext();
var results = db.Translate<SearchResult>(dr);
// figure out how many distinct categories we can find in the entire table:
var distinctCategories = (from sr in results select new { sr.ResultCategoryID }).Distinct();
foreach (var cat in distinctCategories)
{
i += cat.ResultCategoryID;
}
}
}
long result = watch.Stop();
ReportResult(watch, result);
}
