private static Expression ProcessSubquery(ISessionFactory sessionFactory, ICollection <ExpressionHolder> elementExpression, QueryModel queryModel, Expression @group, QueryModel subQueryModel)
{
var resultTypeOverride = subQueryModel.ResultTypeOverride;
if (resultTypeOverride != null && !resultTypeOverride.IsArray && !IsEnumerableOfT(resultTypeOverride))
{
return(null);
}
SubQueryFromClauseFlattener.ReWrite(subQueryModel);
var subQueryMainFromClause = subQueryModel.MainFromClause;
var restrictions = subQueryModel.BodyClauses
.OfType <WhereClause>()
.Select(w => new NhWithClause(w.Predicate));
var join = new NhJoinClause(subQueryMainFromClause.ItemName,
subQueryMainFromClause.ItemType,
subQueryMainFromClause.FromExpression,
restrictions);
queryModel.BodyClauses.Add(@join);
var visitor = new SwapQuerySourceVisitor(subQueryMainFromClause, @join);
queryModel.TransformExpressions(visitor.Swap);
var selector = subQueryModel.SelectClause.Selector;
var collectionType = subQueryModel.GetResultType();
var elementType = selector.Type;
var source = new QuerySourceReferenceExpression(@join);
return(BuildSubCollectionQuery(sessionFactory, elementExpression, @group, source, selector, elementType, collectionType));
}
public static ExpressionToHqlTranslationResults GenerateHqlQuery(QueryModel queryModel, VisitorParameters parameters, bool root,
NhLinqExpressionReturnType?rootReturnType)
{
// Expand conditionals in subquery FROM clauses into multiple subqueries
if (root)
{
// This expander works recursively
SubQueryConditionalExpander.ReWrite(queryModel);
}
NestedSelectRewriter.ReWrite(queryModel, parameters.SessionFactory);
// Remove unnecessary body operators
RemoveUnnecessaryBodyOperators.ReWrite(queryModel);
// Merge aggregating result operators (distinct, count, sum etc) into the select clause
MergeAggregatingResultsRewriter.ReWrite(queryModel);
// Swap out non-aggregating group-bys
NonAggregatingGroupByRewriter.ReWrite(queryModel);
// Rewrite aggregate group-by statements
AggregatingGroupByRewriter.ReWrite(queryModel);
// Rewrite aggregating group-joins
AggregatingGroupJoinRewriter.ReWrite(queryModel);
// Rewrite non-aggregating group-joins
NonAggregatingGroupJoinRewriter.ReWrite(queryModel);
SubQueryFromClauseFlattener.ReWrite(queryModel);
// Rewrite left-joins
LeftJoinRewriter.ReWrite(queryModel);
// Rewrite paging
PagingRewriter.ReWrite(queryModel);
// Flatten pointless subqueries
QueryReferenceExpressionFlattener.ReWrite(queryModel);
// Flatten array index access to query references
ArrayIndexExpressionFlattener.ReWrite(queryModel);
// Add joins for references
AddJoinsReWriter.ReWrite(queryModel, parameters);
// Expand coalesced and conditional joins to their logical equivalents
ConditionalQueryReferenceExpander.ReWrite(queryModel);
// Move OrderBy clauses to end
MoveOrderByToEndRewriter.ReWrite(queryModel);
// Give a rewriter provided by the session factory a chance to
// rewrite the query.
var rewriterFactory = parameters.SessionFactory.Settings.QueryModelRewriterFactory;
if (rewriterFactory != null)
{
var customVisitor = rewriterFactory.CreateVisitor(parameters);
if (customVisitor != null)
{
customVisitor.VisitQueryModel(queryModel);
}
}
// rewrite any operators that should be applied on the outer query
// by flattening out the sub-queries that they are located in
var result = ResultOperatorRewriter.Rewrite(queryModel);
// Identify and name query sources
QuerySourceIdentifier.Visit(parameters.QuerySourceNamer, queryModel);
var visitor = new QueryModelVisitor(parameters, root, queryModel, rootReturnType)
{
RewrittenOperatorResult = result,
};
visitor.Visit();
return(visitor._hqlTree.GetTranslation());
}