How next button in search works - Design problem

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Subject

Author

Date

How next button in search works - Design problem

Arsalan Ahmad

03-28-2006

Re: How next button in search works - Design probl...

Yama

03-28-2006

Re: How next button in search works - Design probl...

Cor Ligthert [M...

03-29-2006

Posted by Arsalan Ahmad on March 28, 2006, 5:36 pm

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Hi,

May be I am a newbie, or may be i dont have that much insight in following
systems ..i.e. why i have some confusions as below:

In many websites, when search is performed on some keywords (not only
including google which perform general search but other sites which perform
seach on a particular type of item in their database) then many search
results are obtained (for example more than 100 or even more than 1000) but
only limited amount of results are displayed in a page (like for example 10
results per page). Thus in order to display the next 10 results, a user has
to click on 'Next' button. Similarly, it is possible that a user can click
on 'Previous' button to display the previous 10 results. My question is what
are different mechanisms to perform this and which one would be most optimal
than others?

Why I am asking this question because, if we are performing a search by
sending a query of keywords to a website then we get following procedure:

Browser->Send Query->ASP.NET page(considering we are using ASP.NET although
it could be PHP or ASP or JSP etc)

Now internally from ASP.NET page, a database connection is opened (say using
ADO.NET) and search is performed by sending a query to database and getting
the results. So we get:

ASP.NET page->Send query to database (using ADO.NET)

Now database returns recordset containing more than lets say 100 records (or
1000 records)

Database->Send back 1000 records->ASP.NET page

And then ASP.NET page send 10 records to client and drop the rest. So:

ASP.NET page->Send 10 records->Client Browser.

So now when the client press Next button what happens? It seems illogical to
send same search query to database and then dropping first 10 records from
recordset and only passing recordset from 11th record to 20th records to
client browser.

So, can anyone please tell me what are different approaches to handle this.

Thanks,

Arsalan

Posted by Yama on March 28, 2006, 9:09 pm

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Hi,

Have you used paging in the past? Here is how you would do a paging query in
T-SQL:

//-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~
SELECT TOP <pageSize> *
FROM
(
SELECT TOP (<pageSize> * <pageIndex>)
< columns names>
FROM
< table name >
WHERE
< condition >
ORDER BY < PK column name > DESC
)
AS anyNameYouWant ORDER BY < PK column name > ASC
//-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~

<pageSize> = the number of records to be retrieved
<pageIndex> = the desired page index (1 based)
<column names> = list of the column names
<table name> = source table name and optional joined tables
<condition> = optional filter condition
< PK column name > = the primary key column name (it has to be also present
into the <column names> list)

Sample T-SQL for getting 5 records from the Northwind Employee table from
the second page:

//-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~
USE Northwind
SELECT TOP 5 *
FROM(
SELECT TOP 10
EmployeeID,
LastName,
FirstName,
Title,
BirthDate,
HireDate
FROM
Employees

ORDER BY EmployeeID DESC

)
AS Employees ORDER BY EmployeeID ASC
//-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~

USE Northwind

-- Page 1
SELECT TOP 3 *
FROM(
SELECT TOP 3
EmployeeID,
LastName,
FirstName,
Title,
BirthDate,
HireDate
FROM
Employees

ORDER BY EmployeeID DESC

)
AS Employees ORDER BY EmployeeID ASC

-- Page 2
SELECT TOP 3 *
FROM(
SELECT TOP 6
EmployeeID,
LastName,
FirstName,
Title,
BirthDate,
HireDate
FROM
Employees

ORDER BY EmployeeID DESC

)
AS Employees ORDER BY EmployeeID ASC

-- Page 3
SELECT TOP 3 *
FROM(
SELECT TOP 9
EmployeeID,
LastName,
FirstName,
Title,
BirthDate,
HireDate
FROM
Employees

ORDER BY EmployeeID DESC

)
AS Employees ORDER BY EmployeeID ASC

If using AJAX you could simply return the results you need depending on page
clicked using Callbacks... You'd be amazed at the speed of execution...

Hope this helps,

Yama Kamyar

> Hi,

> May be I am a newbie, or may be i dont have that much insight in following

> systems ..i.e. why i have some confusions as below:

> In many websites, when search is performed on some keywords (not only

> including google which perform general search but other sites which

> perform seach on a particular type of item in their database) then many

> search results are obtained (for example more than 100 or even more than

> 1000) but only limited amount of results are displayed in a page (like for

> example 10 results per page). Thus in order to display the next 10

> results, a user has to click on 'Next' button. Similarly, it is possible

> that a user can click on 'Previous' button to display the previous 10

> results. My question is what are different mechanisms to perform this and

> which one would be most optimal than others?

> Why I am asking this question because, if we are performing a search by

> sending a query of keywords to a website then we get following procedure:

> Browser->Send Query->ASP.NET page(considering we are using ASP.NET

> although it could be PHP or ASP or JSP etc)

> Now internally from ASP.NET page, a database connection is opened (say

> using ADO.NET) and search is performed by sending a query to database and

> getting the results. So we get:

> ASP.NET page->Send query to database (using ADO.NET)

> Now database returns recordset containing more than lets say 100 records

> (or 1000 records)

> Database->Send back 1000 records->ASP.NET page

> And then ASP.NET page send 10 records to client and drop the rest. So:

> ASP.NET page->Send 10 records->Client Browser.

> So now when the client press Next button what happens? It seems illogical

> to send same search query to database and then dropping first 10 records

> from recordset and only passing recordset from 11th record to 20th records

> to client browser.

> So, can anyone please tell me what are different approaches to handle

> this.

> Thanks,

> Arsalan

Posted by Cor Ligthert [MVP] on March 29, 2006, 1:07 am

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Arsalan,

In ASPNET are for that nice solutions named Paging (as the name is for a
windforms as well).

Here a sample on our page for a webpage (there are as well for windowforms)

http://www.vb-tips.com/default.aspx?ID=5ef272ef-bfcc-4b1f-85f8-6750bb0390f8

For the others search on 'Paging"

I hope this helps,

Cor