db Backups task scheduler

USE [master]

GO

/****** Object:  StoredProcedure [dbo].[sp_BackupDatabases]    Script Date: 11/10/2015 6:10:29 PM ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

-- =============================================

-- Author: Microsoft

-- Create date: 2010-02-06

-- Description: Backup Databases for SQLExpress

-- Parameter1: databaseName

-- Parameter2: backupType F=full, D=differential, L=log

-- Parameter3: backup file location

-- =============================================

ALTER PROCEDURE [dbo].[sp_BackupDatabases] 

            @databaseName sysname = null,

            @backupType CHAR(1),

            @backupLocation nvarchar(200)

AS

       SET NOCOUNT ON;

          

            DECLARE @DBs TABLE

            (

                  ID int IDENTITY PRIMARY KEY,

                  DBNAME nvarchar(500)

            )

          

             -- Pick out only databases which are online in case ALL databases are chosen to be backed up

             -- If specific database is chosen to be backed up only pick that out from @DBs

            INSERT INTO @DBs (DBNAME)

            SELECT Name FROM master.sys.databases

            where state=0

            AND name=@DatabaseName

            OR @DatabaseName IS NULL

            ORDER BY Name

          

            -- Filter out databases which do not need to backed up

            IF @backupType='F'

                  BEGIN

                  DELETE @DBs where DBNAME IN

('tempdb','master','model','msdb' )

                  END

            ELSE IF @backupType='D'

                  BEGIN

                  DELETE @DBs where DBNAME IN

('tempdb','master','model','msdb' )

                  END

            ELSE IF @backupType='L'

                  BEGIN

                  DELETE @DBs where DBNAME IN

('tempdb','master','model','msdb' )

                  END

            ELSE

                  BEGIN

                  RETURN

                  END

          

            -- Declare variables

            DECLARE @BackupName varchar(500)

            DECLARE @BackupFile varchar(500)

            DECLARE @DBNAME varchar(500)

            DECLARE @sqlCommand NVARCHAR(1000)

        DECLARE @dateTime NVARCHAR(20)

            DECLARE @Loop int                 

                      

            -- Loop through the databases one by one

            SELECT @Loop = min(ID) FROM @DBs

      WHILE @Loop IS NOT NULL

      BEGIN

-- Database Names have to be in [dbname] format since some have - or _ in their name

      SET @DBNAME = '['+(SELECT DBNAME FROM @DBs WHERE ID = @Loop)+']'

-- Set the current date and time n yyyyhhmmss format

      SET @dateTime = REPLACE(CONVERT(VARCHAR, GETDATE(),105),'/','') + '_' +  REPLACE(CONVERT(VARCHAR, GETDATE(),108),':','') 

-- Create backup filename in path\filename.extension format for full,diff and log backups

      IF @backupType = 'F'

            SET @BackupFile = @backupLocation+REPLACE(REPLACE(@DBNAME, '[',''),']','')+ '_FULL_'+ @dateTime+ '.BAK'

      ELSE IF @backupType = 'D'

            SET @BackupFile = @backupLocation+REPLACE(REPLACE(@DBNAME, '[',''),']','')+ '_DIFF_'+ @dateTime+ '.BAK'

      ELSE IF @backupType = 'L'

            SET @BackupFile = @backupLocation+REPLACE(REPLACE(@DBNAME, '[',''),']','')+ '_LOG_'+ @dateTime+ '.TRN'

-- Provide the backup a name for storing in the media

      IF @backupType = 'F'

            SET @BackupName = REPLACE(REPLACE(@DBNAME,'[',''),']','') +' full backup for '+ @dateTime

      IF @backupType = 'D'

            SET @BackupName = REPLACE(REPLACE(@DBNAME,'[',''),']','') +' differential backup for '+ @dateTime

      IF @backupType = 'L'

            SET @BackupName = REPLACE(REPLACE(@DBNAME,'[',''),']','') +' log backup for '+ @dateTime

-- Generate the dynamic SQL command to be executed

       IF @backupType = 'F'

                  BEGIN

               SET @sqlCommand = 'BACKUP DATABASE ' +@DBNAME+  ' TO DISK = '''+@BackupFile+ ''' WITH INIT, NAME= ''' +@BackupName+''', NOSKIP, NOFORMAT'

                  END

       IF @backupType = 'D'

                  BEGIN

               SET @sqlCommand = 'BACKUP DATABASE ' +@DBNAME+  ' TO DISK = '''+@BackupFile+ ''' WITH DIFFERENTIAL, INIT, NAME= ''' +@BackupName+''', NOSKIP, NOFORMAT'       

                  END

       IF @backupType = 'L'

                  BEGIN

               SET @sqlCommand = 'BACKUP LOG ' +@DBNAME+  ' TO DISK = '''+@BackupFile+ ''' WITH INIT, NAME= ''' +@BackupName+''', NOSKIP, NOFORMAT'       

                  END

-- Execute the generated SQL command

       EXEC(@sqlCommand)

-- Goto the next database

SELECT @Loop = min(ID) FROM @DBs where ID>@Loop

END

Find nth highest and lowest salary of an Employee

This question has been asked many times in interview to candidate that find or fetch nth highest and lowest salary of an Employee like 2nd, 3rd, 4th, 5th… highest and lowest salary of an Employee from Employee table. This question some times also asked as get nth highest and lowest salary of an Employee without using TOP and sub query. Let’s see solutions for all this questions in this article.

Suppose we have following table of Employee with Name and Salary of Employee.

Query to get nth(3rd) highest salary of an Employee

Suppose we want to get 3rd highest salary of an Employee so query should be like.

select top 1 Salary as '3rd highest salary' from (select distinct top 3 Salary from Employee order by Salary desc)   a order by Salary asc

Let me illustrate above query as here we want to fetch nth(3rd) highest salary of an Employee so first inside sub query we find all top n(3) distinct records using order by descending which result in to top n(3) records with highest salary and than we fetch top 1 record among all these records with order by ascending which full fill our requirement to find nth(3rd) highest salary of an Employee.

Query to get nth(3rd) lowest salary of an Employee

select top 1 Salary as '3rd lowest salary' from (select distinct top 3 Salary from Employee order by Salary asc)   a order by Salary desc

See here we want to find nth(3rd) lowest salary of an Employee so our logical of fetching data will be reversed so first inside sub query we find all top n(3) distinct records using order by ascending which result in to top n(3) records with lowest salary and than we fetch top 1 record among all these records with order by descending which full fill our requirement to find nth(3rd) lowest salary of an Employee.

Query to get nth(3rd) highest salary of an Employee without using TOP and Sub Query

This question also can twisted to find or fetch nth(3rd) highest salary of an Employee without using TOP and Sub Query so solutions can be using With CTE(Common Table Expressions) as below query.

WITH Salaries AS( SELECT distinct Salary, ROW_NUMBER() OVER(ORDER BY Salary DESC) AS 'RowNum'     FROM Employee)SELECT Salary FROM Salaries WHERE RowNum = 3

in above query we find salary in descending order using With CTE(Common Table Expression) than we used RowNum = n(3) which results into nth(3rd) highest salary of an Employee without using TOP and Sub Query.

Query to get nth(3rd) lowest salary of an Employee without using TOP and Sub Query

To find or fetch nth(3rd) lowest salary of an Employee without using TOP and Sub Query so solutions can be using With CTE(Common Table Expressions) as below query.

WITH Salaries AS(SELECT distinct Salary, ROW_NUMBER() OVER(ORDER BY Salary asc) AS 'RowNum'     FROM Employee)SELECT Salary FROM Salaries WHERE RowNum = 3

in above query we find salary in ascending order using With CTE(Common Table Expression) than we used RowNum = n(3) which results into nth(3rd) lowest salary of an Employee without using TOP and Sub Query.

What is cookie? ADVANTAGES AND DISADVANTAGES OF COOKIES

What is cookie?
A cookie is a small piece of text file stored on user's computer in the form of name-value pair. Cookies are used by websites to keep track of visitors e.g. to keep user information like username etc. If any web application using cookies, Server send cookies and client browser will store it. The browser then returns the cookie to the server at the next time the page is requested. The most common example of using a cookie is to store User information, User preferences, Password Remember Option etc.It is also one of the common and mostly asked interview questions.

Some facts about Cookie

Here are a few facts to know about cookies:

Cookies are domain specific i.e. a domain cannot read or write to a cookie created by another domain. This is done by the browser for security purpose.
   
Cookies are browser specific. Each browser stores the cookies in a different location. The cookies are browser specific and so a cookie created in one browser(e.g in Google Chrome) will not be accessed by another browser(Internet Explorer/Firefox).
 
Most of the browsers store cookies in text files in clear text. So it’s not secure at all and no sensitive information should be stored in cookies.
 
Most of the browsers have restrictions on the length of the text stored in cookies. It is 4096(4kb) in general but could vary from browser to browser.

Some browsers limit the number of cookies stored by each domain(20 cookies). If the limit is exceeded, the new cookies will replace the old cookies.

Cookies can be disabled by the user using the browser properties. So unless you have control over the cookie settings of the users (for e.g. intranet application), cookies should not be used.

Cookie names are case-sensitive. E.g. UserName is different than username.
Advantages of using cookies
Here are some of the advantages of using cookies to store session state.

Cookies are simple to use and implement.

Occupies less memory, do not require any server resources and are stored on the user's computer so no extra burden on server.

We can configure cookies to expire when the browser session ends (session cookies) or they can exist for a specified length of time on the client’s computer (persistent cookies).

Cookies persist a much longer period of time than Session state.

Disadvantages of using cookies

Here are some of the disadvantages:

As mentioned previously, cookies are not secure as they are stored in clear text they may pose a possible security risk as anyone can open and tamper with cookies. You can manually encrypt and decrypt cookies, but it requires extra coding and can affect application performance because of the time that is required for encryption and decryption

Several limitations exist on the size of the cookie text(4kb in general), number of cookies(20 per site in general), etc.

User has the option of disabling cookies on his computer from browser’s setting .

Cookies will not work if the security level is set to high in the browser.
 
Users can delete a cookies.

Users browser can refuse cookies,so your code has to anticipate that possibility.
 
Complex type of data not allowed (e.g. dataset etc). It allows only plain text (i.e. cookie allows only string content)

How to find whether a string contains any of the special characters?

 Regex RgxUrl = new Regex("[^a-z0-9]");
                    blnContainsSpecialCharacters = RgxUrl.IsMatch(stringToCheck);

========================================================

public static bool IsSpecialCharacters(this string stringToTest)
       {
           //const string charSet = "[^a-z0-9]";
             const string charSet = "[^a-zA-Z0-9]";

           //Regex RgxUrl = new Regex("[^a-z0-9]");
           //blnContainsSpecialCharacters = RgxUrl.IsMatch(stringToCheck);

           return Regex.Match(stringToTest, @"^[" + charSet + @"]+$").Success;
       }