private VfpLimitExpression GetVfpLimitExpression(VfpLimitExpression limitExpression, VfpScanExpression scanExpression)
{
if (scanExpression == null)
{
return(null);
}
var keyMembers = GetKeyMembers(scanExpression.Target.ElementType.KeyMembers);
if (!keyMembers.Any())
{
return(null);
}
var variableReference = new VfpVariableReferenceExpression(scanExpression.ResultType, GetUniqueVariableName());
var expressionBinding = new VfpExpressionBinding(scanExpression, variableReference);
var sortClauses = GetSortClauses(keyMembers, expressionBinding).ToList().AsReadOnly();
var sortExpression = new VfpSortExpression(scanExpression.ResultType, expressionBinding, sortClauses);
return(new VfpLimitExpression(limitExpression.ResultType,
sortExpression,
limitExpression.Limit,
limitExpression.WithTies));
}
public override VfpExpression Visit(VfpSortExpression expression)
{
// This method should not be called. Sorting is handled in VisitSortClauses.
throw new NotImplementedException();
}
public virtual VfpExpression Visit(VfpSortExpression expression)
{
return(new VfpSortExpression(expression.ResultType,
VisitVfpExpressionBinding(expression.Input),
CreateDbSortClauses(expression.SortOrder)));
}