🚀 go-pugleaf

Wayne Niddery [TeamB] wrote:
> Mitch wrote:
>> I need to enable my users to easily specify (and re-specify) a
>> position for each row relative to the others above and below it. I 
>> therefore
>> can't use the primary key or other columns to sort by. I must use an
>> extra integer column where the sequence is defined by the integer.
>>
>> I am using the Developer Express grid to drag and drop the rows and
>> they have given me code which (upon an insert or drag) automatically
>> recalculates the sequence in the grid, often for all the rows in the
>> dataset.
>>
>> This is done on a row by row basis, so the process is very very slow
>> and gets slower as the number of rows in the dataset increases. Also,
>> in a multi-user situation I suspect this will be unworkable.
> 
> Multiple users can compete on trying to order these rows? There's no good 
> solution for that part.
> 
>> Does anyone have any suggestions for accomplishing this in a way which
>> numbering is automatic for the user, but which maintains the
>> performance and efficiency of a database with > 10,000 rows.
> 
> Use a grid that is not directly attached to the dataset. Could be a 
> stringgird, drawgrid or listview. When the dataset is opened, load the rows 
> into a list of your own objects and use these to display (I strongly 
> recommend a drawgrid or virtual mode listview as this avoids copying data 
> yet again to display it).
> 
> When a user moves an item, you simply need to move that object in the list.
> 
> When the user says he's done, you simply loop through the list *once* 
> updating the sequence numbers in the database. Using a loop with a 
> parameterized update statement within a single transaction should provide 
> decent performance.
> 

Thanks.

Mitch