>>>>>I am trying to implement a simple 'multiple select mover grid' and I find the re-sequencing of the record slow. I am sure there is a way to re-order the records in a shorter time. Can somebody help?
>>>>>
>>>>>I keep a sequence number in the table to order the table. First, the user selects a few records by clicking on the checkbox (flag). Then the user selects the new position for the selected records. When the 'Move' button is click, I tried to sequence it using the following codes
>>>>>
>>>>>nrecno = recno()
>>>>>nseq = sequence
>>>>>replace all sequence with sequence*1000
>>>>>replace all sequence with sequence/1000+nseq*1000 for flag=.T.
>>>>>i=0
>>>>>scan
>>>>> i=i+1
>>>>> replace sequence with i
>>>>>endscan
>>>>>
>>>>>The scan is slow. Is it possible to do it in one replace statement?
>>>>>
>>>>>Can anyone suggest other ways of re-sequencing of records?
>>>>
>>>>Your algorithm is slow because you scan/replace all records in table. I would advise to change sequence value just for records you want to move:
>>>>Select table1 && this is Grid.Recordsource
>>>>Set order to tag sequence
>>>>Calculate min(sequence) to nMinsequence
>>>>nCounter=0
>>>>Scan For flag=.t. && have tag on flag for better performance
>>>> nCounter=nCounter+1
>>>> Replace table1.Sequence with nMinsequence-nCounter
>>>>Endscan
>>>>Thisform.Grid1.Refresh
>>>
>>>Sorry, I think there is a misunderstanding. I didn't phrase my question clear enough.
>>>
>>>My user can select any records on the grid. Then he can move all the selected records to a specific location he choose. For example, I have,
>>>
>>>seq desc Flag
>>>1 Rec1 .F.
>>>2 Rec2 .T.
>>>3 Rec3 .F.
>>>4 Rec4 .T.
>>>5 Rec5 .F.
>>>6 Rec6 .F.
>>>
>>>The users selected Rec2 & Rec4 as shown. He choose position Rec5 to move to. On 'move', I would get
>>>
>>>seq desc Flag
>>>1 Rec1 .F.
>>>2 Rec3 .F.
>>>3 Rec5 .F.
>>>4 Rec2 .T.
>>>5 Rec4 .T.
>>>6 Rec6 .F.
>>>
>>>He can also choose to move records up and ideally, he can do the kind of thing like select Rec1 & Rec5 and move them to Rec3 too.
>>>
>>>Is there a way to replace all with a running number in a faster way?
>>
>>Well, you can have additional field 'addseq' and compound tag on two fields "sequence" and "addseq". When you want to move selected records to particular place, you :
>>1. Replace all selected records sequence with 'placeholder' sequence (the same number for all these records).
>>2. Scan selected records and fill addseq value with 1,2,3... (all other records will have 0).
>>Surely, your code should be sophisticated enough to provide moving new bunch of records to the same place.
>
>Theoretically, I will get many records with the same 'placeholder' sequence and when the users want to move among the records with the same placeholder, I will come back to the same problem.
>
>I tried using three SQL SELECT ...INTO ARRAY and three APPEND FROM ARRAY and it seems faster. The only problem is I need to use table buffering and if I am not wrong, SQL SELECT doesn't get the newest data from buffer (the flags). I need to use a temp table again. It makes the whole thing complicated.
>
>Looks like I am in deep shit.

I have several tables in an application that has a similar sequence field. Jsut my opinion, and you may not be doing this, but I believe it is a big mistake to write your code to require all records to have a sequential sequence number with no gaps in sequence. It is to difficult to maintain. Every time you delete a record you have to update you sequence numbers. You will do less coding overall and have better performance if your only requirement is unique sequnce numbers.

If gaps in sequence are permited, here is my solution.

nrecno = recno()
nseq = sequence
select *,recno() as ntrecno from into cursor mycursor where flag = .t.
nRecords = _Tally
replace sequence with sequence+nrecords for Sequence>nSeq
i=0
select mycursor
scan
i = i+1
goto ntrecno in
replace sequence with nSeq + i in
endscan
select