Database Strategy

[Michael Doub]

The potential size of the database is causing me to drive the database by loading the data grid by catching 
command GetDataForLine pLine, @pOutData.

On the first execution thru the OpenCard handler everything works just fine.  On subsequent 
calls the OpenCursor routine is never executed.  The handler seems get as far as the 

set the dgProp[ "show vscrollbar" ] of group "DataGrid" to true  that 

statement where it would appear that that the OpenCard handler is terminated.   If I make
the setup_Scrolling code a comment, then everything works as as I would have expected.
it is really odd that the same code executes fine on the first execution.   Could this be a bug
in the data grid code?  I am using 5.0.1 (rc 1)


on OpenCard
   log ("Open Card") 
   set the tmLabel of group "Header" of this card to the short name of this card
   setup_Scrolling
   OpenCursor
   put revDatabaseColumnNames(sCursorID) into sRecordFields
   put revNumberOfRecords(sCursorID) into sRecordCount
   lock screen
   set the dgNumberOfRecords of group "DataGrid" to sRecordCount
   unlock screen
end OpenCard

on setup_Scrolling
   if the environment is "mobile" then
      set the dgProp[ "show vscrollbar" ] of group "DataGrid" to false
      -- other code remove for now
   else
      set the dgProp[ "show vscrollbar" ] of group "DataGrid" to true
   end if
end setup_Scrolling



On 2011-11-16, at 1:04 PM, Pete wrote:

> Sounds like the problem is that you close the cursor when the card is
> closed.  From that point, it's not a valid cursor, as you're finding when
> you return to the card.  When you return to the card, you'd need to either
> leave the cursor open or re-execute the SELECT statement that created it.
> 
> Depending on the needs of your application, you might want to consider
> not creating a cursor but returning the data from the SELECT statement
> directly to your application using revDataFromQuery and storing that in a
> custom property.  That's useful if you are using a datagrid on your card
> since you can simply set the dgtext of the datagrid to the returned data to
> populate the datagrid.
> 
> Pete
> Molly's Revenge <http://www.mollysrevenge.com>
> 
> 
> 
> 
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