Re: Record navigation with Paging

Thanks for the info Ryan,

The main thing is i don't want to keep more than 5 pages
of data (5*30) in the memory. Also the main focus is user
should be able to navigate with single record, in addtion
to a page navigation.
Also in my application the UI is build with unmanaged MFC
app and only the storage access layer is in the mananged
DDLL with ADO.NET. So i would like to build the custom
DataView to accomodate these requirement.

Also the Table need to maintain a fixed number of records.
(only last n(20,000) rows should be remain in the table).

Any more thoughts??

-Hari

>-----Original Message-----
>I'd use a DataTable, build a dataview on it, store it in
session state, and
>then just set the RowFilter property
>http://www.knowdotnet.com/articles/advancedrowfilter.html
to filter the
>data. 20,000 rows is a buttload of data and it's
doubtful that you need that
>much data at one time - if you can use 5,000 and cache
it, then if they
>select something in the next 5,000 hit the db again, and
the same for the
>next 5,000 but assuming you do, you don't want to make
unnecessary trips
>back to the db each time. If the user erroneously
clicks forward then
>backward, you don't want to make two trips to the db on
an accident. A
>DataView is probably the more efficient way to go in
this scenario but as
>with anything, the devil will be in the details.
>
>--
>W.G. Ryan MVP (Windows Embedded)
>
>TiBA Solutions
>www.tibasolutions.com | www.devbuzz.com |
www.knowdotnet.com
>"Hari" <anonymous@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
message
>news:191901c53ca9$5d2b3720$a601280a@xxxxxxxxxx
>> Hi,
>>
>> Iam working with a custom grid control to navigate
>> navigate large number of records from a table.
>> The control need to have row up, row down, page up,
page
>> down features.
>>
>> Requirements are :
>> page size = 30 records
>> maximum records in database table - 20,000 (each
record
>> 150K)
>>
>> I was looking the msdn sample:(Paging through a query
>> result) its shows building dynamic query for every
pages.
>> So inorder to this way, if i want to navigate a singe
row
>> ( up/down (one record) do i need to build a query every
>> time? or is there any better way to approach this??
>>
>> please help me guys......
>>
>> Hari
>>
>> The sample i was looking :
>> case "Next":
>> selCmd.CommandText = "SELECT TOP " + pageSize
+ "
>> CustomerID, CompanyName FROM Customers " +
>> "WHERE CustomerID > @CustomerId
>> ORDER BY CustomerID";
>> selCmd.Parameters.Add("@CustomerId",
>> SqlDbType.VarChar, 5).Value = lastVisibleCustomer;
>> break;
>> case "Previous":
>> selCmd.CommandText = "SELECT TOP " + pageSize
+ "
>> CustomerID, CompanyName FROM Customers " +
>> "WHERE CustomerID < @CustomerId
>> ORDER BY CustomerID DESC";
>> selCmd.Parameters.Add("@CustomerId",
>> SqlDbType.VarChar, 5).Value = firstVisibleCustomer;
>> break;
>> default:
>> selCmd.CommandText = "SELECT TOP " + pageSize
+ "
>> CustomerID, CompanyName FROM Customers ORDER BY
>> CustomerID";
>>
>> // Determine total pages.
>> SqlCommand totCMD = new SqlCommand("SELECT
Count
>> (*) FROM Customers", nwindConn);
>> nwindConn.Open();
>> int totalRecords = (int)totCMD.ExecuteScalar();
>> nwindConn.Close();
>> totalPages = (int)Math.Ceiling((double)
>> totalRecords / pageSize);
>>
>> break;
>>
>>
>>
>
>
>.
>
.