public override Expression Visit(Expression node)
{
var visited = base.Visit(node);
switch (visited)
{
case GroupByResultExpression groupByResultExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupByResultExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(VisitMethodCall));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
var outerKeySelector = groupByResultExpression.OuterKeySelector;
var innerKeySelector = updater.Visit(groupByResultExpression.InnerKeySelector);
var elementSelector = updater.Visit(groupByResultExpression.ElementSelector);
var elements
= new EnumerableRelationalQueryExpression(
newSelectExpression
.UpdateProjection(new ServerProjectionExpression(elementSelector))
.AddToPredicate(Expression.Equal(outerKeySelector, innerKeySelector)));
return(ExpandGroup(visited, outerKeySelector, elements));
}
case GroupedRelationalQueryExpression groupedRelationalQueryExpression:
{
var outerKeySelector = groupedRelationalQueryExpression.OuterKeySelector;
var innerKeySelector = groupedRelationalQueryExpression.InnerKeySelector;
if (groupedRelationalQueryExpression.RequiresDenullification)
{
outerKeySelector = JoinKeyDenullifyingExpressionVisitor.Instance.Visit(outerKeySelector);
innerKeySelector = JoinKeyDenullifyingExpressionVisitor.Instance.Visit(innerKeySelector);
}
var elements
= new EnumerableRelationalQueryExpression(
groupedRelationalQueryExpression.SelectExpression
.AddToPredicate(
Expression.Equal(
outerKeySelector,
innerKeySelector)));
return(ExpandGroup(visited, groupedRelationalQueryExpression.OuterKeySelector, elements));
}
default:
{
return(visited);
}
}
}
public override Expression Visit(Expression node)
{
IEnumerable <string> GetNameParts()
{
return(currentPath.Reverse().Where(n => n != null && !n.StartsWith("<>")));
}
switch (node)
{
case null:
{
return(null);
}
case NewExpression newExpression:
{
if (newExpression.Members == null)
{
return(newExpression);
}
var arguments = newExpression.Arguments.ToArray();
for (var i = 0; i < newExpression.Members.Count; i++)
{
currentPath.Push(newExpression.Members[i].GetPathSegmentName());
arguments[i] = Visit(arguments[i]);
currentPath.Pop();
}
return(newExpression.Update(arguments));
}
case MemberInitExpression memberInitExpression:
{
var newExpression = (NewExpression)Visit(memberInitExpression.NewExpression);
var bindings = memberInitExpression.Bindings.ToArray();
for (var i = 0; i < bindings.Length; i++)
{
currentPath.Push(bindings[i].Member.GetPathSegmentName());
bindings[i] = VisitMemberBinding(bindings[i]);
currentPath.Pop();
}
return(memberInitExpression.Update(newExpression, bindings));
}
case GroupByResultExpression groupByResultExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupByResultExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(Visit));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
currentPath.Push("Key");
var outerKeySelector = Visit(groupByResultExpression.OuterKeySelector);
var innerKeySelector = updater.Visit(groupByResultExpression.InnerKeySelector);
var elementSelector = updater.Visit(groupByResultExpression.ElementSelector);
currentPath.Pop();
return(new GroupedRelationalQueryExpression(
newSelectExpression.UpdateProjection(new ServerProjectionExpression(elementSelector)),
outerKeySelector,
innerKeySelector,
groupByResultExpression.InnerKeyLambda,
requiresDenullification: false,
type: groupByResultExpression.Type));
}
case GroupedRelationalQueryExpression groupedRelationalQueryExpression:
{
var uniquifier = new TableUniquifyingExpressionVisitor();
var oldSelectExpression = groupedRelationalQueryExpression.SelectExpression;
var newSelectExpression = uniquifier.VisitAndConvert(oldSelectExpression, nameof(Visit));
var oldTables = oldSelectExpression.Table.Flatten().ToArray();
var newTables = newSelectExpression.Table.Flatten().ToArray();
var updater = new TableUpdatingExpressionVisitor(oldTables, newTables);
currentPath.Push("Key");
var outerKeySelector = Visit(groupedRelationalQueryExpression.OuterKeySelector);
var innerKeySelector = updater.Visit(groupedRelationalQueryExpression.InnerKeySelector);
currentPath.Pop();
return(new GroupedRelationalQueryExpression(
newSelectExpression,
outerKeySelector,
innerKeySelector,
groupedRelationalQueryExpression.InnerKeyLambda,
groupedRelationalQueryExpression.RequiresDenullification,
groupedRelationalQueryExpression.Type));
}
case DefaultIfEmptyExpression defaultIfEmptyExpression:
{
var expression = sqlColumnNullabilityExpressionVisitor.Visit(Visit(defaultIfEmptyExpression.Expression));
var parts = GetNameParts().Append("$empty");
var name = string.Join(".", parts);
var flag = new SqlColumnExpression(targetTable, name, typeof(bool?), true);
return(new DefaultIfEmptyExpression(expression, flag));
}
case PolymorphicExpression polymorphicExpression:
{
return(new PolymorphicExpression(
polymorphicExpression.Type,
Visit(polymorphicExpression.Row),
polymorphicExpression.Descriptors));
}
case AnnotationExpression annotationExpression:
{
return(VisitExtension(annotationExpression));
}
default:
{
var parts = GetNameParts();
var isNullable = !node.Type.GetTypeInfo().IsValueType;
switch (node)
{
case SqlColumnExpression sqlColumnExpression:
{
parts = parts.DefaultIfEmpty(sqlColumnExpression.ColumnName);
isNullable = sqlColumnExpression.IsNullable;
break;
}
case SqlAliasExpression sqlAliasExpression:
{
parts = parts.DefaultIfEmpty(sqlAliasExpression.Alias);
break;
}
}
return(new SqlColumnExpression(
targetTable,
string.Join(".", parts),
node.Type,
isNullable));
}
}
}
