1CREATE VIEW(7) PostgreSQL 9.2.24 Documentation CREATE VIEW(7)
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6 CREATE_VIEW - define a new view
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9 CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW name [ ( column_name [, ...] ) ]
10 [ WITH ( view_option_name [= view_option_value] [, ... ] ) ]
11 AS query
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14 CREATE VIEW defines a view of a query. The view is not physically
15 materialized. Instead, the query is run every time the view is
16 referenced in a query.
17 CREATE OR REPLACE VIEW is similar, but if a view of the same name
19 already exists, it is replaced. The new query must generate the same
20 columns that were generated by the existing view query (that is, the
21 same column names in the same order and with the same data types), but
22 it may add additional columns to the end of the list. The calculations
23 giving rise to the output columns may be completely different.
24 If a schema name is given (for example, CREATE VIEW myschema.myview
26 ...) then the view is created in the specified schema. Otherwise it is
27 created in the current schema. Temporary views exist in a special
28 schema, so a schema name cannot be given when creating a temporary
29 view. The name of the view must be distinct from the name of any other
30 view, table, sequence, index or foreign table in the same schema.
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33 TEMPORARY or TEMP
34 If specified, the view is created as a temporary view. Temporary
35 views are automatically dropped at the end of the current session.
36 Existing permanent relations with the same name are not visible to
37 the current session while the temporary view exists, unless they
38 are referenced with schema-qualified names.
39 If any of the tables referenced by the view are temporary, the view
41 is created as a temporary view (whether TEMPORARY is specified or
42 not).
43 name
45 The name (optionally schema-qualified) of a view to be created.
46 column_name
48 An optional list of names to be used for columns of the view. If
49 not given, the column names are deduced from the query.
50 WITH ( view_option_name [= view_option_value] [, ... ] )
52 This clause specifies optional parameters for a view; currently,
53 the only supported parameter name is security_barrier, which should
54 be enabled when a view is intended to provide row-level security.
55 See Section 37.4, “Rules and Privileges”, in the documentation for
56 full details.
57 query
59 A SELECT(7) or VALUES(7) command which will provide the columns and
60 rows of the view.
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63 Currently, views are read only: the system will not allow an insert,
64 update, or delete on a view. You can get the effect of an updatable
65 view by creating INSTEAD triggers on the view, which must convert
66 attempted inserts, etc. on the view into appropriate actions on other
67 tables. For more information see CREATE TRIGGER (CREATE_TRIGGER(7)).
68 Another possibility is to create rules (see CREATE RULE
69 (CREATE_RULE(7))), but in practice triggers are easier to understand
70 and use correctly.
71 Use the DROP VIEW (DROP_VIEW(7)) statement to drop views.
73 Be careful that the names and types of the view's columns will be
75 assigned the way you want. For example:
76 CREATE VIEW vista AS SELECT 'Hello World';
78 is bad form in two ways: the column name defaults to ?column?, and the
80 column data type defaults to unknown. If you want a string literal in a
81 view's result, use something like:
82 CREATE VIEW vista AS SELECT text 'Hello World' AS hello;
84 Access to tables referenced in the view is determined by permissions of
86 the view owner. In some cases, this can be used to provide secure but
87 restricted access to the underlying tables. However, not all views are
88 secure against tampering; see Section 37.4, “Rules and Privileges”, in
89 the documentation for details. Functions called in the view are treated
90 the same as if they had been called directly from the query using the
91 view. Therefore the user of a view must have permissions to call all
92 functions used by the view.
93 When CREATE OR REPLACE VIEW is used on an existing view, only the
95 view's defining SELECT rule is changed. Other view properties,
96 including ownership, permissions, and non-SELECT rules, remain
97 unchanged. You must own the view to replace it (this includes being a
98 member of the owning role).
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101 Create a view consisting of all comedy films:
102 CREATE VIEW comedies AS
104 SELECT *
105 FROM films
106 WHERE kind = 'Comedy';
107 This will create a view containing the columns that are in the film
109 table at the time of view creation. Though * was used to create the
110 view, columns added later to the table will not be part of the view.
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113 The SQL standard specifies some additional capabilities for the CREATE
114 VIEW statement:
115 CREATE VIEW name [ ( column_name [, ...] ) ]
117 AS query
118 [ WITH [ CASCADED | LOCAL ] CHECK OPTION ]
119 The optional clauses for the full SQL command are:
121 CHECK OPTION
123 This option has to do with updatable views. All INSERT and UPDATE
124 commands on the view will be checked to ensure data satisfy the
125 view-defining condition (that is, the new data would be visible
126 through the view). If they do not, the update will be rejected.
127 LOCAL
129 Check for integrity on this view.
130 CASCADED
132 Check for integrity on this view and on any dependent view.
133 CASCADED is assumed if neither CASCADED nor LOCAL is specified.
134 CREATE OR REPLACE VIEW is a PostgreSQL language extension. So is the
136 concept of a temporary view.
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139 ALTER VIEW (ALTER_VIEW(7)), DROP VIEW (DROP_VIEW(7))
140PostgreSQL 9.2.24 2017-11-06 CREATE VIEW(7)