|
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;
using Signum.Utilities;
using Signum.Utilities.ExpressionTrees;
using Signum.Entities.DynamicQuery;
namespace Signum.Engine.Linq
{
internal class RowNumberFiller : DbExpressionVisitor
{
static internal Expression Fill(Expression expression)
{
return new RowNumberFiller().Visit(expression);
}
SourceExpression innerSource;
protected override Expression VisitSelect(SelectExpression select)
{
Expression top = this.Visit(select.Top);
SourceExpression from = this.VisitSource(select.From);
Expression where = this.Visit(select.Where);
SourceExpression last = innerSource;
innerSource = from;
ReadOnlyCollection<ColumnDeclaration> columns = this.VisitColumnDeclarations(select.Columns);
innerSource = last;
ReadOnlyCollection<OrderExpression> orderBy = this.VisitOrderBy(select.OrderBy);
ReadOnlyCollection<Expression> groupBy = this.VisitGroupBy(select.GroupBy);
if (top != select.Top || from != select.From || where != select.Where || columns != select.Columns || orderBy != select.OrderBy || groupBy != select.GroupBy)
return new SelectExpression(select.Alias, select.Distinct, select.Reverse, top, columns, from, where, orderBy, groupBy);
return select;
}
protected override Expression VisitRowNumber(RowNumberExpression rowNumber)
{
if (rowNumber.OrderBy == null || rowNumber.OrderBy.IsEmpty())
{
SelectExpression inner = (SelectExpression)innerSource;
var cols = inner.Columns.Select(cd => new OrderExpression(OrderType.Ascending, cd.GetReference(inner.Alias)));
return new RowNumberExpression(cols.ToReadOnly());
}
return base.VisitRowNumber(rowNumber);
}
}
}
|
By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.
If a file you wish to view isn't highlighted, and is a text file (not binary), please
let us know and we'll add colourisation support for it.
I'm Computer Scientist, one of the founders of Signum Software, and the lead developer behind Signum Framework.
www.signumframework.com
I love programming in C#, Linq, Compilers, Algorithms, Functional Programming, Computer Graphics, Maths...