private static ShowPlanNode BuildConstant(BoundConstantRelation node)
{
var properties = Enumerable.Empty <KeyValuePair <string, string> >();
var children = Enumerable.Empty <ShowPlanNode>();
return(new ShowPlanNode(@"Constant", properties, children));
}
private static BoundRelation RewriteDisjunctions(BoundExpression condition)
{
var scalarPredicates = new List <BoundExpression>();
var relationalPredicates = new List <BoundRelation>();
foreach (var disjunction in Expression.SplitDisjunctions(condition))
{
BoundExistsSubselect exists;
bool isNegated;
if (TryGetExistsSubselect(disjunction, out exists, out isNegated))
{
if (!isNegated)
{
relationalPredicates.Add(exists.Relation);
}
else
{
var constantRelation = new BoundConstantRelation();
var predicate = new BoundJoinRelation(BoundJoinType.LeftAntiSemi, constantRelation, exists.Relation, null, null, null);
relationalPredicates.Add(predicate);
}
}
else if (Expression.IsConjunction(disjunction))
{
var constantRelation = new BoundConstantRelation();
var output = RewriteConjunctions(constantRelation, disjunction);
if (output == null)
{
scalarPredicates.Add(disjunction);
}
else
{
var predicate = new BoundJoinRelation(BoundJoinType.LeftSemi, constantRelation, output, null, null, null);
relationalPredicates.Add(predicate);
}
}
else
{
scalarPredicates.Add(disjunction);
}
}
if (relationalPredicates.Count == 0)
{
return(null);
}
if (scalarPredicates.Count > 0)
{
var constantRelation = new BoundConstantRelation();
var predicate = Expression.Or(scalarPredicates);
var filter = new BoundFilterRelation(constantRelation, predicate);
relationalPredicates.Insert(0, filter);
}
return(new BoundConcatenationRelation(relationalPredicates, Enumerable.Empty <BoundUnifiedValue>()));
}
private static BoundQuery CreateBoundQuery(BoundExpression expression)
{
var factory = new ValueSlotFactory();
var valueSlot = new ValueSlot(factory, @"result", 0, expression.Type);
var computedValue = new BoundComputedValue(expression, valueSlot);
var constantRelation = new BoundConstantRelation();
var computeRelation = new BoundComputeRelation(constantRelation, new[] { computedValue });
var projectRelation = new BoundProjectRelation(computeRelation, new [] { valueSlot });
var columnSymbol = new QueryColumnInstanceSymbol(valueSlot.Name, valueSlot);
return(new BoundQuery(projectRelation, new[] { columnSymbol }));
}
private static CardinalityEstimate EstimateConstantRelation(BoundConstantRelation relation)
{
return(CardinalityEstimate.SingleRow);
}
