protected HqlTreeNode VisitSubQueryExpression(SubQueryExpression expression)
{
ExpressionToHqlTranslationResults query = QueryModelVisitor.GenerateHqlQuery(expression.QueryModel, _parameters, false, null);
return(query.Statement);
}
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());
}