Large RowSet

[dutch]

Dear Mr.Rao,

Can I do like below to read Large RowSet?

oRs := RowSet() limit with 1000 records.
XBROWSE oLbx

oLbx:bChange := {|| if(oRs:RecCount()=oRs:RecNo(), (oRs:ReadNext(1000), oLbx:Refresh()), ) }

Thanks in advance.

[richard-service]

Dear Mr.Rao,

Can I do like below to read Large RowSet?

oRs := RowSet() limit with 1000 records.
XBROWSE oLbx

oLbx:bChange := {|| if(oRs:RecCount()=oRs:RecNo(), (oRs:ReadNext(1000), oLbx:Refresh()), ) }

Thanks in advance.

Hi Dutch,
How about use this

Code: Select all  Expand view

oServer:SelectDB(cLoginTable)
::oDB := oServer:Query("SELECT * FROM postmsf ORDER BY zipcode LIMIT 1000")
 

[dutch]

Hi Richard,

Thank you, But I mean
1. read 1000 records with xbrowse
2. read until hit the bottom (1,000) and then read more 1,000 from server.
3. xbrowse will show 2,000 now.

It will reduce reading time for 1 activate and read more after hit the bottom. This is my idea need.

Hi Dutch,
How about use this

Code: Select all  Expand view

oServer:SelectDB(cLoginTable)
::oDB := oServer:Query("SELECT * FROM postmsf ORDER BY zipcode LIMIT 1000")
 

Regards,
Dutch

[Marc Venken]

XBrowse is already optimized for this.

There was a topic about it :

viewtopic.php?f=3&t=32264&hilit=xbrowse+limit

[Rick Lipkin]

Dutch

Not sure how you are creating your recordset .. I always define my oRs object with local cache

Code: Select all  Expand view

oRsAcc := TOleAuto():New( "ADODB.Recordset" )
oRsAcc:CursorType     := 1        // opendkeyset
oRsAcc:CursorLocation := 3        // local cache
oRsAcc:LockType       := 3        // lockoportunistic

cSQL := "SELECT * FROM ACCIDENT  order by date"

TRY
   oRsAcc:Open(cSQL,xConnect )
CATCH oErr
   MsgInfo( "Error in Opening ACCIDENT table" )
   RETURN(.F.)
END TRY
 

The Local Cache option allows the fetched Cursor to reside on the client rather to be on the Server. Traversing a local cursor is VERY fast ..

Rick Lipkin

[nageswaragunupudi]

Please try this sample

Code: Select all  Expand view

#include "fivewin.ch"

function Main()

   local oCn, oRs

   oCn   := FW_DemoDB(1) // if you have FWH17.01
                 // if not you establish connection to your server

   oRs   := oCn:RowSet( "custbig", 1000 )
   oRs:lAutoExpand := .t.

   XBROWSER oRs FASTEDIT SHOW RECID //AUTOFIT

   oCn:Close()

return nil
 

During browse, keep pressing down arrow or page down button and you keep seeing the rowset growing automatically.

Incidentally the table `custbig` on the demo server has one million records.

Note: If you connect to your server, instead of "custbig" use any large table name. Make sure the table has a primary key.

Mr Rick
This is FWH library for MySql.
This is not possible with any other alternative

[nageswaragunupudi]

Mr Dutch

You can also try this example.
Connect using oCn := FW_DemoDB( 1 )
viewtopic.php?f=3&t=32737&p=194525&hilit=large+rowsets#p194525

[dutch]

Dear Mr.Rao,

What is the different of 2 samples? If I use sql statement, how does it work? Because it has some other clause that we have to use.
1st Example It's working as you said.

Code: Select all  Expand view

Function main
oRs   := oServer:RowSet( "fogst", 1000 )
oRs:lAutoExpand := .t.

XBROWSER oRs SHOW SLNUM FASTEDIT
oServer:close()
return nil

2nd Example This sample is not working

Code: Select all  Expand view

Function main
oRs   := oServer:RowSet( "select * from fogst limit 1000")
oRs:lAutoExpand := .t.

XBROWSER oRs SHOW SLNUM FASTEDIT
oServer:close()
return nil

Please try this sample

Code: Select all  Expand view

#include "fivewin.ch"

function Main()

   local oCn, oRs

   oCn   := FW_DemoDB(1) // if you have FWH17.01
                 // if not you establish connection to your server

   oRs   := oCn:RowSet( "custbig", 1000 )
   oRs:lAutoExpand := .t.

   XBROWSER oRs FASTEDIT SHOW RECID //AUTOFIT

   oCn:Close()

return nil
 

During browse, keep pressing down arrow or page down button and you keep seeing the rowset growing automatically.

Incidentally the table `custbig` on the demo server has one million records.

Note: If you connect to your server, instead of "custbig" use any large table name. Make sure the table has a primary key.

Mr Rick
This is FWH library for MySql.
This is not possible with any other alternative

[nageswaragunupudi]

Code: Select all  Expand view

oRs   := oServer:RowSet( "select * from fogst limit 1000")
 

This does not work.
Please tell the rowset object the size of the limit by indicating in a separate parameter.
Also, either you use name of table or in case of SQL, let it end with ORDER BY <primarykey>
Please do either if you want to take advantage of the expand feature

So,
Either
oRs := oServer:RowSet( "fogst", 1000 )
or
oRs := oServer:RowSet( "select ..... from fogst order by <primarykey>", 1000 )

[dutch]

Dear Mr.Rao,

It works great. It reduce the time to fetch and automatic re-fetch records.

Another question, it use the same parameter (nLimit) with ::QueryResult()
::QueryResult(cSql,nLimit)

Thanks.

[nageswaragunupudi]

No.