CREATE VIEW - Constructs a virtual table
SYNOPSIS
CREATE VIEW view AS SELECT query
INPUTS
view The name of a view to be created.
query An SQL query which will provide the columns and
rows of the view.
Refer to the SELECT statement for more information
about valid arguments.
OUTPUTS
CREATE The message returned if the view is successfully
created.
ERROR: Relation 'view' already exists
This error occurs if the view specified already
exists in the database.
NOTICE create: attribute named "column" has an unknown
type
The view will be created having a column with an
unknown type if you do not specify it. For example,
the following command gives a warning:
CREATE VIEW vista AS SELECT 'Hello World'
whereas this command does not:
CREATE VIEW vista AS SELECT text 'Hello World'
DESCRIPTION
CREATE VIEW will define a view of a table. This view is
not physically materialized. Specifically, a query rewrite
retrieve rule is automatically generated to support
retrieve operations on views.
NOTES
Currently, views are read only.
Use the DROP VIEW statement to drop views.
Create a view consisting of all Comedy films:
CREATE VIEW kinds AS
SELECT *
FROM films
WHERE kind = 'Comedy';
SELECT * FROM kinds;
code | title | did | date_prod | kind | len
-------+---------------------------+-----+------------+--------+-------
UA502 | Bananas | 105 | 1971-07-13 | Comedy | 01:22
C_701 | There's a Girl in my Soup | 107 | 1970-06-11 | Comedy | 01:36
(2 rows)
COMPATIBILITY
SQL92
SQL92 specifies some additional capabilities for the CRE
ATE VIEW statement:
CREATE VIEW view [ column [, ...] ]
AS SELECT expression [ AS colname ] [, ...]
FROM table [ WHERE condition ]
[ WITH [ CASCADE | LOCAL ] CHECK OPTION ]
The optional clauses for the full SQL92 command are:
CHECK OPTION
This option is to do with updatable views. All
INSERTs and UPDATEs on the view will be checked to
ensure data satisfy the view-defining condition. If
they do not, the update will be rejected.
LOCAL Check for integrity on this view.
CASCADE
Check for integrity on this view and on any depen
dent view. CASCADE is assumed if neither CASCADE
nor LOCAL is specified.
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