System.Data.Common.CommandTrees.DbExpression.Element()

Here are the examples of the csharp api class System.Data.Common.CommandTrees.DbExpression.Element() taken from open source projects. By voting up you can indicate which examples are most useful and appropriate.

private DbExpression RewriteElementExpression(DbElementExpression expression)
        {
            DbExpression rewrittenInput = Rewrite(expression.Argument);
            if (!object.ReferenceEquals(expression.Argument, rewrittenInput))
            {
                expression = rewrittenInput.Element();
            }
            return expression;
        }

protected override CqtExpression TranslateUnary(ExpressionConverter parent, CqtExpression operand, MethodCallExpression call)
                {
                    CqtExpression result = LimitResult(parent, operand);

                    // If this FirstOrDefault/SingleOrDefault() operation is the root of the query,
                    // then the evaluation is performed in the client over the resulting set,
                    // to provide the same semantics as Linq to Objects. Otherwise, an Element
                    // expression is applied to retrieve the single element (or null, if empty)
                    // from the output set.
                    if (!parent.IsQueryRoot(call))
                    {
                        result = result.Element();
                        result = AddDefaultCase(parent, result, call.Type);
                    }

                    // Span is preserved over First/FirstOrDefault with or without a predicate
                    Span inputSpan = null;
                    if (parent.TryGetSpan(operand, out inputSpan))
                    {
                        parent.AddSpanMapping(result, inputSpan);
                    }

                    return result;
                }

internal override CqtExpression Translate(ExpressionConverter parent, MethodCallExpression call)
                {
                    // Convert the input set and the predicate into a filter expression
                    CqtExpression input = base.Translate(parent, call);

                    // If this First/FirstOrDefault/Single/SingleOrDefault is the root of the query,
                    // then the actual result will be produced by evaluated by
                    // calling First/Single() or FirstOrDefault() on the filtered input set,
                    // which is limited to at most one element by applying a limit.
                    if (parent.IsQueryRoot(call))
                    {
                        // Calling ExpressionConverter.Limit propagates the Span.
                        return RestrictResult(parent, input);
                    }
                    else
                    {
                        CqtExpression element = input.Element();
                        element = FirstTranslatorBase.AddDefaultCase(parent, element, call.Type);

                        // Span is preserved over First/FirstOrDefault with or without a predicate
                        Span inputSpan = null;
                        if (parent.TryGetSpan(input, out inputSpan))
                        {
                            parent.AddSpanMapping(element, inputSpan);
                        }

                        return element;
                    }
                }

public override DbExpression Visit(SingleRowOp op, Node n)
        {
            RelOpInfo inputInfo/n ..... /n //View Source file for more details /n }