CREATE MATERIALIZED VIEW — define a new materialized view
CREATE MATERIALIZED VIEW [ IF NOT EXISTS ]table_name
[ (column_name
[, ...] ) ] [ USINGmethod
] [ WITH (storage_parameter
[=value
] [, ... ] ) ] [ TABLESPACEtablespace_name
] ASquery
[ WITH [ NO ] DATA ]
CREATE MATERIALIZED VIEW
defines a materialized view of
a query. The query is executed and used to populate the view at the time
the command is issued (unless WITH NO DATA
is used) and may be
refreshed later using REFRESH MATERIALIZED VIEW
.
CREATE MATERIALIZED VIEW
is similar to
CREATE TABLE AS
, except that it also remembers the query used
to initialize the view, so that it can be refreshed later upon demand.
A materialized view has many of the same properties as a table, but there
is no support for temporary materialized views.
IF NOT EXISTS
Do not throw an error if a materialized view with the same name already exists. A notice is issued in this case. Note that there is no guarantee that the existing materialized view is anything like the one that would have been created.
table_name
The name (optionally schema-qualified) of the materialized view to be created.
column_name
The name of a column in the new materialized view. If column names are not provided, they are taken from the output column names of the query.
USING method
This optional clause specifies the table access method to use to store
the contents for the new materialized view; the method needs be an
access method of type TABLE
. See Chapter 60 for more information. If this option is not
specified, the default table access method is chosen for the new
materialized view. See default_table_access_method
for more information.
WITH ( storage_parameter
[= value
] [, ... ] )
This clause specifies optional storage parameters for the new
materialized view; see
Storage Parameters in the
CREATE TABLE documentation for more
information. All parameters supported for CREATE
TABLE
are also supported for CREATE MATERIALIZED
VIEW
.
See CREATE TABLE for more information.
TABLESPACE tablespace_name
The tablespace_name
is the name
of the tablespace in which the new materialized view is to be created.
If not specified, default_tablespace is consulted.
query
A SELECT, TABLE, or VALUES command. This query will run within a security-restricted operation; in particular, calls to functions that themselves create temporary tables will fail.
WITH [ NO ] DATA
This clause specifies whether or not the materialized view should be
populated at creation time. If not, the materialized view will be
flagged as unscannable and cannot be queried until REFRESH
MATERIALIZED VIEW
is used.
CREATE MATERIALIZED VIEW
is a
LightDB extension.