protected virtual void OptimizeJoinClause(
[NotNull] JoinClause joinClause,
[NotNull] QueryModel queryModel,
int index,
[NotNull] Action baseVisitAction,
[NotNull] MethodInfo operatorToFlatten,
bool outerJoin = false)
{
Check.NotNull(joinClause, nameof(joinClause));
Check.NotNull(queryModel, nameof(queryModel));
Check.NotNull(baseVisitAction, nameof(baseVisitAction));
Check.NotNull(operatorToFlatten, nameof(operatorToFlatten));
RequiresClientJoin = true;
var previousQuerySource = FindPreviousQuerySource(queryModel, index);
var previousSelectExpression
= previousQuerySource != null
? TryGetQuery(previousQuerySource)
: null;
var previousSelectProjectionCount
= previousSelectExpression?.Projection.Count ?? -1;
baseVisitAction();
if (previousSelectExpression != null)
{
var selectExpression = TryGetQuery(joinClause);
if (selectExpression != null)
{
var sqlTranslatingExpressionVisitor
= _sqlTranslatingExpressionVisitorFactory.Create(this);
var predicate
= sqlTranslatingExpressionVisitor
.Visit(
Expression.Equal(
joinClause.OuterKeySelector,
joinClause.InnerKeySelector));
if (predicate != null)
{
QueriesBySource.Remove(joinClause);
previousSelectExpression.RemoveRangeFromProjection(previousSelectProjectionCount);
var tableExpression = selectExpression.Tables.Single();
var projection
= QueryCompilationContext
.QuerySourceRequiresMaterialization(joinClause)
? selectExpression.Projection
: Enumerable.Empty <Expression>();
var joinExpression
= !outerJoin
? previousSelectExpression.AddInnerJoin(tableExpression, projection)
: previousSelectExpression.AddOuterJoin(tableExpression, projection);
joinExpression.Predicate = predicate;
if (outerJoin)
{
var outerJoinOrderingExtractor = new OuterJoinOrderingExtractor();
outerJoinOrderingExtractor.Visit(predicate);
foreach (var expression in outerJoinOrderingExtractor.Expressions)
{
previousSelectExpression
.AddToOrderBy(new Ordering(expression, OrderingDirection.Asc));
}
}
Expression
= _queryFlattenerFactory
.Create(
joinClause,
QueryCompilationContext,
operatorToFlatten,
previousSelectProjectionCount)
.Flatten((MethodCallExpression)Expression);
RequiresClientJoin = false;
}
}
}
if (RequiresClientJoin)
{
CheckClientEval(joinClause);
}
}
public override void VisitAdditionalFromClause(
AdditionalFromClause fromClause, QueryModel queryModel, int index)
{
Check.NotNull(fromClause, nameof(fromClause));
Check.NotNull(queryModel, nameof(queryModel));
base.VisitAdditionalFromClause(fromClause, queryModel, index);
RequiresClientSelectMany = true;
var selectExpression = TryGetQuery(fromClause);
if (selectExpression != null &&
selectExpression.Tables.Count == 1)
{
var previousQuerySource = FindPreviousQuerySource(queryModel, index);
if (previousQuerySource != null &&
!RequiresClientJoin)
{
var previousSelectExpression = TryGetQuery(previousQuerySource);
if (previousSelectExpression != null)
{
if (!QueryCompilationContext.QuerySourceRequiresMaterialization(previousQuerySource))
{
previousSelectExpression.ClearProjection();
previousSelectExpression.IsProjectStar = false;
}
var readerOffset = previousSelectExpression.Projection.Count;
var correlated = selectExpression.IsCorrelated();
if (correlated)
{
if (!QueryCompilationContext.IsLateralJoinSupported)
{
return;
}
previousSelectExpression
.AddLateralJoin(selectExpression.Tables.First(), selectExpression.Projection);
}
else
{
previousSelectExpression
.AddCrossJoin(selectExpression.Tables.First(), selectExpression.Projection);
}
QueriesBySource.Remove(fromClause);
Expression
= _queryFlattenerFactory
.Create(
fromClause,
QueryCompilationContext,
LinqOperatorProvider.SelectMany,
readerOffset)
.Flatten((MethodCallExpression)Expression);
RequiresClientSelectMany = false;
}
}
}
if (RequiresClientSelectMany)
{
CheckClientEval(fromClause);
}
}