void Execute(MethodCallExpression dsQueryExpression)
{
var orderByFinder = new OrderByFinder();
var orderByExpression = orderByFinder.GetOrderBy(dsQueryExpression);
// .. Continue on processing the OrderBy expression
}
protected override SqlSelect GenerateSkipTake(SqlSelect sequence, SqlExpression skipExp, SqlExpression takeExp)
{
if (skipExp == null)
{
return(base.GenerateSkipTake(sequence, skipExp, takeExp));
}
Debug.Assert(skipExp != null);
var skipCount = (int)((SqlValue)skipExp).Value;
var alias = new SqlAlias(sequence);
var selection = new SqlAliasRef(alias);
var select = new SqlSelect(selection, alias, dominatingExpression);
if (takeExp == null)
{
return(base.GenerateSkipTake(sequence, skipExp, takeExp));
}
var type = sequence.SourceExpression.Type;
if (type.IsGenericType)
{
var args = type.GetGenericArguments();
if (args.Length == 1)
{
var mappingTable = Services.Model.GetTable(args[0]);
if (mappingTable != null)
{
return(base.GenerateSkipTake(sequence, skipExp, takeExp));
}
}
}
var takeCount = (int)((SqlValue)takeExp).Value;
select.Top = sql.Value(typeof(int), typeProvider.From(typeof(int)), takeCount, false,
dominatingExpression);
sequence.Top = sql.Value(typeof(int), typeProvider.From(typeof(int)), takeCount + skipCount, false,
dominatingExpression);
var finder = new OrderByFinder();
var orderby = finder.GetOrderBy(sequence);
foreach (var item in orderby)
{
if (item.OrderType == SqlOrderType.Descending)
{
select.OrderBy.Add(new SqlOrderExpression(SqlOrderType.Ascending, orderby[0].Expression));
}
else
{
select.OrderBy.Add(new SqlOrderExpression(SqlOrderType.Descending, orderby[0].Expression));
}
}
alias = new SqlAlias(select);
selection = new SqlAliasRef(alias);
select = new SqlSelect(selection, alias, dominatingExpression);
foreach (var item in orderby)
{
select.OrderBy.Add(new SqlOrderExpression(item.OrderType, item.Expression));
}
return(select);
}