Loop on table

-matrix-

Hi everybody!

I need to do a loop on table from the end to begin, do you think that this code is right?

TBTable.ASCENDING(FALSE);
TBTable.SETRANGE();
IF TBTable.FINDFIRST THEN BEGIN
   REPEAT
   ......... 
  ........... 
   UNTIL (TBTable.NEXT = -1);

Sog

No, I think the code is not good.
Because you use a findfirst and choose a repeat afterwards (use findset or find('-'))
and second: next = 0 instead of next = -1 (This might be good, but I never use it) I find it too ambigous with next(-1)

Troubles_In_Paradise

-matrix- wrote:

Hi everybody!

I need to do a loop on table from the end to begin, do you think that this code is right?

TBTable.ASCENDING(FALSE);
TBTable.SETRANGE();
IF TBTable.FINDFIRST THEN BEGIN
   REPEAT
   ......... 
  ........... 
   UNTIL (TBTable.NEXT = -1);

try with:

IF TBTable.FINDSET THEN BEGIN
   REPEAT
   ......... 
  ........... 
   UNTIL (TBTable.NEXT = 0);

take a look to "Next function (Record)" in OnLine help.
Edit: sorry to repeat what sog has already sad! =D>

-matrix-

Thanks for replies boys but is needful the ASCENDING with this sintax ?

mohana_cse06

Did you try?

Item.ASCENDING(FALSE);
IF Item.FINDFIRST THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT = 0;

hemantOne

Hi,

I think if you want records in Descending Order and you do not get by findset after Ascending(False).
May be you need a key or doing some efforts by other way...

mohana_cse06

-matrix- wrote:

Thanks for replies boys but is needful the ASCENDING with this sintax ?

FINDSET can only retrieve records in ascending order.

Sog

Why do you think we didn't comment on the ascending: that part is correct.
ascending false will effectively sort the table in reverse.
The alternative was using a find('+') and using until table.next(-1) = 0

Mohanna, You ought not to use findfirst in a loop!

-matrix-

Yes, I'm trying and It seems work with the FINDSET and with THE FINFIRST =D>

mohana_cse06

Sog wrote:

Mohanna, You ought not to use findfirst in a loop!

Agree with you.

Sog

I'm starting to get confused. Help tells me findset can only be used in descending order, which tells me default ascending is already false: Could you try with ascending(true)?
if that doesn't work, use find('-')
And please don't use findfirst, it's not meant for looping. (findfirst does a select top(1) from table) if nav detects a loop it uses a second query. while findset and find('-') only use 1 query to get the data.

-matrix-

But so if I can't use the FINDSET what is the right instruction?

mohana_cse06

Item.ASCENDING(FALSE);
IF Item.FIND('-') THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT = 0;

Belias

Sog wrote:

I'm starting to get confused. Help tells me findset can only be used in descending order

i think you misread the help (or i misread you rpost )

FINDSET can only retrieve records in ascending order

[/quote]

Sog

I did not misread the help, just a different version

NAV 5.0 SP1 help wrote:

Furthermore, FINDSET only supports descending loops. If you want to loop from the bottom up, you should use FIND(‘+’).

NAV 2009 Developer and IT Pro Documentation wrote:

FINDSET can only retrieve records in ascending order. If you want to loop from the bottom up, then you should use FIND('+').

kriki

mohana_cse06 wrote:

Item.ASCENDING(FALSE);
IF Item.FIND('-') THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT = 0;

This is the correct way. (or also ASCENDING(TRUE) and FIND('+') and NEXT(-1)
But in certain cases, a better way may exist.
The FIND('-') creates a cursor in SQL that is slow and heavy on the system.
If you have few records (<= # of records in recordset ; defined in File=Database=Alter=>Tab advanced), it is better to use FINDSET and read them in ASCENDING and save them in a temptable and then read them in descending. If you code is run a lot of times by a lot of users, this makes it a lot less heavy on the system.

Item.ASCENDING(TRUE); //Ascending!
IF Item.FINDSET THEN
  REPEAT
    tmpItem := Item;
    tmpItem.INSERT(FALSE);
  UNTIL Item.NEXT = 0;

tmpItem.RESET;
tmpItem.ASCENDING(FALSE);
IF tmpItem.FIND('-') THEN
  REPEAT
    Message('%1',tmpItem."No.");
  UNTIL tmpItem.NEXT = 0;

BTW: see also http://www.mibuso.com/howtoinfo.asp?FileID=22

mabl4367

Sog is right.

Usually you sould try to avoid Find('-') and Find('+') but in this senario you can ither

sort in descending order, find the first record and step forward:

Item.ASCENDING(FALSE);
IF Item.FIND('-') THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT = 0;

or

sort in ascending order, find the last record and step backward:

Item.ASCENDING(TRUE);
IF Item.FIND('+') THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT(-1) = 0;

-matrix-

Thanks to Everybody for the numberous replies =D> , I used this solution :

Item.ASCENDING(FALSE);
IF Item.FIND('-') THEN
  REPEAT
    Message('%1',Item."No.");
  UNTIL Item.NEXT = 0;