Apr 14, 2011

Disable Back Button in Browser using JavaScript

By Tarun | Apr 14, 2011 | Tags:
10 comments

 While we are developing any web application then some times it's necessary to disable the back button effect from the browser. This is common in banking websites and other sites where security is major concern. User may hit the back button from the browser and forget to log out from the site.

There fore it's required to disable browser's back button.

So here is the code which will prevent user to go back on previous page.
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>New event</title>
</head>
<SCRIPT type="text/javascript">
window.history.forward();
function noBack() { window.history.forward(); }
</SCRIPT>
</HEAD>
<BODY onload="noBack();"
onpageshow="if (event.persisted) noBack();" onunload="">
<a href='page2.html' >Page 2</a>
</body>
</html>

Code for Page 1.


<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>New event</title>
</head>

</HEAD>
<BODY>
Page 2
</body>
</html>

Code for page 2.

Here I have given 2 pages page 1 and page 2. From page 1 I am going to page 2 using page 2 link. Now if I will click on page 2's browser back button it will go to page 1 but from page 1 it will again forward to page 2 so user can't go to the page 1 using back button.

Note : Above code is tested in IE 9.0 and Firefox 3.6.8

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Apr 8, 2011

Concatenation in SQL, Using For XML PATH(), Concatenate more than one rows in one field

By Tarun | Apr 8, 2011 | Tags:
4 comments



Some times it is required to concatenate more no of rows into one single filed separated by commas. There are some options for that like we can write our own UDF for that, in sql server built in COALESCE function is there with this function we can achieve it. But some time need is different or we want to achieve it in different way then there is another option that I am going to explain using FOR XML PATH().

Let me first show me my table design








and also show me the data which I have inserted for this testing purpose



Have you tried to access data in xml format from sql table, not yet ? Then try below query and see the result.
SELECT Employee_Name FROM Emp_Tech FOR XML path('')





When you run above query then you can see result like <Employee Name>Tarun</Employee Name>.... conti... and when you click on the resulted row then it will open .xml file in query window. But here we are understanding how to merge that all the rows into single row with comma separated so let me write a query for that.
SELECT
DISTINCT
Employee_tech,employee_name =
substring( (SELECT
',' + Employee_Name
FROM
Emp_Tech et2
Where
et2.Employee_Tech = et1.Employee_Tech
FOR XML PATH(''), ELEMENTS
),2,500)

FROM
Emp_Tech et1
And this is the out put for that query

Out put





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Apr 6, 2011

List all the table in given database

By Tarun | Apr 6, 2011 | Tags:
0 comments

Think that you have a database more than 1-2 hundred database tables and you want to get list of all the tables in particular database. I was working on a project with more than 356 table and required to get the list of all the table with column names, column types and length of data type so first I searched for list of table finding query and it give me different different result.

Then I thought let me write a quick post about all the available query which can list all the tables from specific database.

For a demo purpose I have created only 2 tables in one database and write a query for quick result and better image

Let's check one by one.


SELECT * FROM information_schema.tables

Above query will return the data from information_schema table. It has only tables related info.

look at the result with below screen shot



SELECT * FROM sysobjects WHERE xtype='U'

Above query will retrieve result from system object table which have all the information related to database like Primary Key, Stored Procedure, User table etc....

look at the result with below screen shot


SELECT * FROM Sys.Tables

Above query get the result along with object_id which will be very useful for join if you want to get column names etc. This object id will be tied with other table.

look at the result with below screen shot



exec sp_msforeachtable 'print ''?'''

Above query is little bit different than all other options. It will simply prints table name on the screen rather than returning a result in table.

look at the result with below screen shot




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Apr 2, 2011

How to use Rank( ), Dense_Rank( ) and Row_Number( ) function

By Tarun | Apr 2, 2011 | Tags:
2 comments

Understanding Row Number Function

Here we will see the Row_Number(), Rank() and Dense_Rank()
function with details and example

Look at the Figure 1  which has some data and in next
figure 2 we are going to explain about the use of above mentioned function.



Above figure has query and result we can see that there are 14
rows with column jobid, job_disc, minimum value and maximum
value.


Now see figure 2



Using ROW_NUMBER() Function

In figure 2 we can see the result of ROW_NUMBER() function, it just a sequential order starts from 1 to the number of rows returns within a result set.

Using RANK() Function

In figure 2 we can see the result of RANK() function, If result of two or more rows are same then it will give same rank and put a gap of repeated no of rows in next sequential number for next row. As we can see in figure 2 for row number 2,3 and 4 has same rank as 2, and for row number 5 it direct assign rank 5 and eliminate rank 3 and 4 because it's repeated in previous row.

Using DENSE_RANK() Function

In figure 2 we can see the result of DENSE_RANK() function, if result of two or more rows are same then it will assign same rank but for the next rank of next row it will not put any gap and assign continuous number to the next rank of next row. Like above example it will not eliminate rank 3 and 4. It will assign rank 3 for row number 5th.

Enjoy Reading ..........

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Apr 1, 2011

Find All The Database Name in SQL SERVER

By Tarun | Apr 1, 2011 | Tags:
5 comments

Get all the available database in SQL Server, using following command.

Following all the command will list all the database on SQL Server.


--In SQL Server 2008

--This is the Stored Procedure which will retrieve database name and size in kb and remark

Exec sp_databases



This stored procedure will retrieve more column then previous sp and return size in mb rather than kb.
And owner of db, created date, and status of the database like status, updatability, useraccessibility etc.

Exec sp_helpdb



and finally below 2 sps will retrieve detailed information about the database mostly in technical terms.

 Technically terms in the sense dbid,status, file path etc.

Select * From sys.databases



Select * From sys.sysdatabases



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A new way to communicate -- April fool by google 2011

By Tarun | Tags:
2 comments
The mouse and keyboard were invented before the Internet even existed. Since then, countless technological advancements have allowed for much more efficient human computer interaction. Why then do we continue to use outdated technology? Introducing Gmail Motion -- now you can control Gmail with your body.


See here  https://mail.google.com/mail/help/motion.html

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