Mysql Alter View

View is a virtual table, act like a table but actually it does not contain data. The view is the outcome result set of a SELECT statement.

Mysql Alter View

Mysql Alter View

     

View is a virtual table, act like a table but  actually it does not contain data. The view is the outcome result set of a SELECT statement. A view include  rows and columns from one or more than one tables. A View is  a query that is stored as an object. It is simply a subset of table's column. View ensures security mechanism to the table. Alter View is used to modify and change the definition of  view.

Query to create table:

The create table employee is used to create a table employee with a primary key (Empid). 

 

 

 

 

CREATE TABLE `employees` (
            ->Empid int(10),  
            ->Empname varchar(60),
             ->date date 
	     ->PRIMARY KEY(Empid)
           ->);

Query to insert data into Table named employees:

The Query insert into is used to add the records or rows to the table 'employees'.

mysql>insert into employees values(01,'Girish','2008-12-22');
Query OK, 1 row affected (0.02 sec)
mysql>insert into employee1 values(02,'Komal','2008-12-23');
Query OK, 1 row affected (0.02 sec)

Query to view data of  Table named employees:

To view the detail from table 'employees' we run the select Query that return you  the records from table 'employees'.

mysql> select * from employees;

Output:-

+-------+---------+------------+
| Empid | Empname | date       |
+-------+---------+------------+
|     1 | Girish  | 2008-12-22 |
|     2 | Komal   | 2008-12-23 |
+-------+---------+------------+
2 rows in set (0.00 sec)

Query to create view of Table named employees:

The Query below create a 'view Emp' and return the select records from table 'Emp'.

mysql> create view Emp
    -> as Select employees.empname,employees.date
    -> from employees;
Query OK, 0 rows affected (0.00 sec)

Query to see the records in view:

To see the detail of table emp view , we use select Query that return the detail of  emp.

mysql> select * from emp;
+---------+------------+
| empname | date       |
+---------+------------+
| Girish  | 2008-12-22 |
| Komal   | 2008-12-23 |
+---------+------------+
2 rows in set (0.00 sec)

Query to alter view:

The Query alter view is used to modify the table view emp and include all the records from table 'emp'. 

mysql> alter view emp as select * from employees;
Query OK, 0 rows affected (0.00 sec)

Query to see the data of the altered view:-

mysql> select * from emp;
+-------+---------+------------+
| Empid | Empname | date       |
+-------+---------+------------+
|     1 | Girish  | 2008-12-22 |
|     2 | Komal   | 2008-12-23 |
+-------+---------+------------+
2 rows in set (0.00 sec)