Difference between revisions of "View"

Revision as of 15:40, 14 November 2017

A view is the representation of a SQL statement that is stored in memory so that it can easily be re-used
- A view gives a view of the table as defined by the select statement in the view defination
- View does not store data separately
- Only definition (query) of the view is stored
- the data is retrieved from the underlying table based on the view definition

CREATE VIEW customer_south AS
SELECT customer_id, first_name, region
FROM customer
WHERE lower(region) = 'south'

EXECUTE the VIEW

SELECT * FROM customer_south

this will run the view

CREATE OR REPLACE VIEW customer_south AS
SELECT customer_id, first_name, country,region
FROM customer
WHERE lower(region) = 'south'

Updating records in a view will update the underlying table

UPDATE customer_south
SET address_line1 = "1123 Main street"
WHERE customer_id = 10;

@@ Line 21: / Line 21: @@
 ==UPDATING THE VIEW==
+Updating records in a view will update the underlying table
+ UPDATE customer_south
+ SET address_line1 = "1123 Main street"
+ WHERE customer_id = 10;
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