예제 #1
0
        public static void ReWrite(QueryModel queryModel, ISessionFactory sessionFactory)
        {
            var nsqmv = new NestedSelectDetector(sessionFactory);

            nsqmv.Visit(queryModel.SelectClause.Selector);
            if (!nsqmv.HasSubqueries)
            {
                return;
            }

            var elementExpression = new List <ExpressionHolder>();
            var group             = Expression.Parameter(typeof(IGrouping <Tuple, Tuple>), "g");

            var replacements = new Dictionary <Expression, Expression>();

            foreach (var expression in nsqmv.Expressions)
            {
                var processed = ProcessExpression(queryModel, sessionFactory, expression, elementExpression, group);
                if (processed != null)
                {
                    replacements.Add(expression, processed);
                }
            }

            var key = Expression.Property(group, IGroupingKeyProperty);

            var expressions = new List <ExpressionHolder>();

            var identifier = GetIdentifier(sessionFactory, new QuerySourceReferenceExpression(queryModel.MainFromClause));

            var rewriter = new SelectClauseRewriter(key, expressions, identifier, replacements);

            var resultSelector = rewriter.Visit(queryModel.SelectClause.Selector);

            elementExpression.AddRange(expressions);

            var keySelector = CreateSelector(elementExpression, 0);

            var elementSelector = CreateSelector(elementExpression, 1);

            var input = Expression.Parameter(typeof(IEnumerable <object>), "input");

            var lambda = Expression.Lambda(
                Expression.Call(GroupByMethod,
                                Expression.Call(CastMethod, input),
                                keySelector,
                                elementSelector),
                input);

            queryModel.ResultOperators.Add(new ClientSideSelect2(lambda));
            queryModel.ResultOperators.Add(new ClientSideSelect(Expression.Lambda(resultSelector, @group)));

            var initializers = elementExpression.Select(e => ConvertToObject(e.Expression));

            queryModel.SelectClause.Selector = Expression.NewArrayInit(typeof(object), initializers);
        }
예제 #2
0
        private static LambdaExpression MakeSelector(ICollection <ExpressionHolder> elementExpression, Expression @select, Expression identifier)
        {
            var parameter = Expression.Parameter(typeof(Tuple), "value");

            var rewriter = new SelectClauseRewriter(parameter, elementExpression, identifier, 1, new Dictionary <Expression, Expression>());

            var selectorBody = rewriter.Visit(@select);

            return(Expression.Lambda(selectorBody, parameter));
        }