public IExecutionPlanOperation GetRootOperation()
{
// If no join then single table select/delete.
if (!joins.Any())
{
if (filters.Any())
{
// Try to get a filter which can use an index.
var indexScanFilter = TryGetFilterWithIndex(filters);
var firstFilter = indexScanFilter.Key;
var table = database.GetTable(firstFilter.Table);
IExecutionPlanOperation predecessor = null;
if (indexScanFilter.Value != null)
{
var readOperation = new NonUniqueScanOperation(table, indexScanFilter.Value, firstFilter, repository,
KeyValue.GetDatabaseFileName(database.Name), table.Name);
predecessor = readOperation;
}
else
{
var readOperation = new FullScanOperation(table, repository, KeyValue.GetDatabaseFileName(database.Name),
table.Name);
predecessor = new FilterOperation(readOperation, firstFilter);
}
filters.Remove(firstFilter);
for (int i = 0; i < filters.Count; i++)
{
var operation = new FilterOperation(predecessor, filters.ElementAt(i));
predecessor = operation;
}
if (selections.Any())
{
predecessor = new SelectOperation(predecessor, selections.First());
}
return predecessor;
}
else
{
var selection = selections.First();
var table = database.GetTable(selection.Table);
var fullScanOperation = new FullScanOperation(table, repository, KeyValue.GetDatabaseFileName(database.Name), table.Name);
return new SelectOperation(fullScanOperation, selection);
}
}
else
{
// Handle selections with join operation.
return null;
}
}
public IExecutionPlanOperation GetRootOperation()
{
// If no join then single table select/delete.
if (!joins.Any())
{
if (filters.Any())
{
// Try to get a filter which can use an index.
var indexScanFilter = TryGetFilterWithIndex(filters);
var firstFilter = indexScanFilter.Key;
var table = database.GetTable(firstFilter.Table);
IExecutionPlanOperation predecessor = null;
if (indexScanFilter.Value != null)
{
var readOperation = new NonUniqueScanOperation(table, indexScanFilter.Value, firstFilter, repository,
KeyValue.GetDatabaseFileName(database.Name), table.Name);
predecessor = readOperation;
}
else
{
var readOperation = new FullScanOperation(table, repository, KeyValue.GetDatabaseFileName(database.Name),
table.Name);
predecessor = new FilterOperation(readOperation, firstFilter);
}
filters.Remove(firstFilter);
for (int i = 0; i < filters.Count; i++)
{
var operation = new FilterOperation(predecessor, filters.ElementAt(i));
predecessor = operation;
}
if (selections.Any())
{
predecessor = new SelectOperation(predecessor, selections.First());
}
return(predecessor);
}
else
{
var selection = selections.First();
var table = database.GetTable(selection.Table);
var fullScanOperation = new FullScanOperation(table, repository, KeyValue.GetDatabaseFileName(database.Name), table.Name);
return(new SelectOperation(fullScanOperation, selection));
}
}
else
{
// Handle selections with join operation.
return(null);
}
}