With HTML5, it is possible for the web pages to store the data locally in the user's browser. This web storage is much faster and secured than the cookies. Also, a larger amount of data can be stored without causing any adverse effect to the performance of the website. 

The data here is not included with every server request. It is used ONLY when it is asked for. It is only that particular web page that can access the data stored by itself.

There are many ways to find second highest salary of Employee in SQL, you can either use SQL Join or Subquery to solve this problem. Here is SQL query using Subquery :

SELECT MAX(Salary) from Employee WHERE Salary NOT IN (select MAX(Salary) FROM Employee );

SELECT  * from Employees  WHERE  upper(EmpName) like upper('joe%');

Master database is system database and it contains information about running server's configuration. When SQL Server 2005 is installed it usually creates master, model, msdb, tempdb resource and distribution system database by default. Only Master database is th one which is absolutely must have database. Without Master database SQL Server cannot be started. This is the reason it is extremely important to backup Master database.

To rebuild the Master database, Run Setup.exe, verify, and repair a SQL Server instance, and rebuild the system databases. This procedure is most often used to rebuild the master database for a corrupted installation of SQL Server.

They get stored in System Catalog Views sys.server_principals and sys.sql_logins.

- A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.

- A non clustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf node of a non clustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.

Constraints enable the RDBMS to enforce the integrity of the database automatically, without the need to create triggers, rule or defaults.

Types of Constraints: NOT NULL, CHEQUE, UNIQUE, PRIMARY KEY, FOREIGN KEY.

Similarity: Both WHERE and HAVING Clause filters out records based on one or more conditions.

Difference: WHERE Clause can only be applied to a static non-aggregated column whereas HAVING is needed for aggregated columns.