Oracle View

In Oracle, view is a virtual table that does not physically exist. It is stored in Oracle data dictionary and do not store any data. It can be executed when called.

A view is created by a query joining one or more tables.

Oracle CREATE VIEW

Syntax:

CREATE VIEW view_name AS
SELECT columns
FROM tables
WHERE conditions;

Parameters:

view_name: It specifies the name of the Oracle VIEW that you want to create.

Example:

Let's take an example to create view. In this example, we are creating two tables suppliers and orders first.

Suppliers table:

CREATE TABLE "SUPPLIERS"
( "SUPPLIER_ID" NUMBER,
"SUPPLIER_NAME" VARCHAR2(4000),
"SUPPLIER_ADDRESS" VARCHAR2(4000)
)
/

Orders table:

CREATE TABLE "ORDERS"
( "ORDER_NO." NUMBER,
"QUANTITY" NUMBER,
"PRICE" NUMBER
)
/

Execute the following query to create a view name sup_orders.

Create View Query:

CREATE VIEW sup_orders AS
SELECT suppliers.supplier_id, orders.quantity, orders.price
FROM suppliers
INNER JOIN orders
ON suppliers.supplier_id = supplier_id
WHERE suppliers.supplier_name = 'VOJO';

Output:

View created.
0.21 seconds

You can now check the Oracle VIEW by this query:

SELECT * FROM sup_orders;

Output:

SUPPLIER_ID	QUANTITY	PRICE
  3	         35	          70
  3	         26	         125
  3	         18	         100
3 rows returned in 0.00 seconds

Oracle Update VIEW

In Oracle, the CREATE OR REPLACE VIEW statement is used to modify the definition of an Oracle VIEW without dropping it.

Syntax:

CREATE OR REPLACE VIEW view_name AS
SELECT columns
FROM table
WHERE conditions;

Example:

Execute the following query to update the definition of Oracle VIEW called sup_orders without dropping it.

CREATE or REPLACE VIEW sup_orders AS
SELECT suppliers.supplier_id, orders.quantity, orders.price
FROM suppliers
INNER JOIN orders
ON suppliers.supplier_id = supplier_id
WHERE suppliers.supplier_name = 'HCL';

You can now check the Oracle VIEW by this query:

SELECT * FROM sup_orders;

Output:

SUPPLIER_ID	QUANTITY	PRICE
      1	         35	         70
      1	         26	        125
      1	         18	        100
row(s) 1 - 3 of 3

Oracle DROP VIEW

The DROP VIEW statement is used to remove or delete the VIEW completely.

Syntax:

DROP VIEW view_name;

Example:

DROP VIEW sup_orders;

DATABASE

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Orcale SQL Tutorial

Create View

Oracle View

Oracle CREATE VIEW

Oracle Update VIEW

Oracle DROP VIEW