public static List <PossibleKey> Find_PossibleKeys(AErgTupel _Ret)
{
LogHelper.LogApp($"{MethodBase.GetCurrentMethod().Name}");
//Possible key list
List <PossibleKey> _pkl = new List <PossibleKey>();
//Functional dependency count
Dictionary <string, int> _fdc = new Dictionary <string, int>();
foreach (string _attr in _Ret.FunctionalDependencyGrid.Keys)
{
_fdc.Add(_attr, _Ret.FunctionalDependencyGrid[_attr].Count(e => e.Value.HasValue && e.Value.Value));
}
//Turn dictionary to List for sorting
List <KeyValuePair <string, int> > _fdc_list = _fdc.ToList();
//Sort by Amount DESC
_fdc_list.Sort((a, b) => b.Value.CompareTo(a.Value));
//Find metric for best
int max_fd = _fdc.First().Value;
//Remove leser than best
_fdc_list.RemoveAll(a => a.Value != max_fd);
//Order by Amount of Attributes ASC
_fdc_list.Sort((a, b) => a.Key.Count(c => c == ',').CompareTo(b.Key.Count(d => d == ',')));
//Find metric for least Attributes
int least_attr = _fdc_list.First().Key.Count(a => a == ',') + 1;
//Remove lesser that best
_fdc_list.RemoveAll(a => a.Key.Count(b => b == ',') + 1 != least_attr);
//Convert back to Dictionary
_fdc = _fdc_list.ToDictionary(a => a.Key, a => a.Value);
if (_fdc.Count > 0)
{
List <string> _loc_attrb = null;
foreach (string _str_attrb in _fdc.Keys)
{
string _str_clean = _str_attrb.Replace("[", "").Replace("]", "");
_loc_attrb = new List <string>(_str_clean.Split(','));
_pkl.Add(new PossibleKey(_Ret.Relation)
{
Attributes = _loc_attrb, Coverage = (double)max_fd / (double)(_Ret.FunctionalDependencyGrid.First().Value.Count - least_attr)
});
}
}
return(_pkl);
}
public static AErgTupel Analysis(string Database, string Relation)
{
AErgTupel _Ret = new AErgTupel(Database, Relation, DPAnalysis.AttributAnalyse_Results[Relation].First().Count_Rows.Value);
_Ret.DocumentedKey = DPTupel_Helper.Get_DocumentedKey(Relation);
_Ret.DocumentedDpenedencies = DPTupel_Helper.Get_DocumentedDependencies(Relation);
if (DPAnalysis.AttributAnalyse_Results_Sort[Relation].First().Value.Count_Rows > 0)
{
_Ret.FunctionalDependencyGrid = DPTupel_Helper.CreateDependencyMatrixA(_Ret.Relation);
}
if (_Ret.FunctionalDependencyGrid != null && _Ret.DocumentedKey == null)
{
_Ret.PossibleKeys = DPTupel_Helper.Find_PossibleKeys(_Ret);
}
return(_Ret);
}
