.. _materialized_view_dialog:

*********************************
`Materialized View Dialog`:index:
*********************************

Use the *Materialized View* dialog to define a materialized view. A materialized
view is a stored or cached view that contains the result set of a query. Use
the REFRESH MATERIALIZED VIEW command to update the content of a materialized
view.

The *Materialized View* dialog organizes the development of a materialized_view
through the following dialog tabs: *General*, *Definition*, *Storage*,
*Parameter*, and *Security*. The *SQL* tab displays the SQL code generated by
dialog selections.

.. image:: images/materialized_view_general.png
    :alt: Materialized view dialog general tab
    :align: center

Use the fields in the *General* tab to identify the materialized view:

* Use the *Name* field to add a descriptive name for the materialized view. The
  name will be displayed in the *pgAdmin* tree control.
* Use the drop-down listbox next to *Owner* to select the role that will own
  the materialized view.
* Select the name of the schema in which the materialized view will reside from
  the drop-down listbox in the *Schema* field.
* Store notes about the materialized view in the *Comment* field.

Click the *Definition* tab to continue.

.. image:: images/materialized_view_definition.png
    :alt: Materialized view dialog storage tab
    :align: center

Use the fields in the *Storage* tab to maintain the materialized view:

* Move the *With Data* switch to the *Yes* position to specify the materialized
  view should be populated at creation time. If not, the materialized view
  cannot be queried until you invoke REFRESH MATERIALIZED VIEW.
* Use the drop-down listbox next to *Tablespace* to select a location for the
  materialized view.
* Use the drop-down list box next to Access Method to specify the table access method to use to store the contents
  for the new materialized view; the method needs to be an access method of type TABLE. This field is optional.
  This option is available from v12 and above.
* Use the *Fill Factor* field to specify a fill factor for the materialized
  view. The fill factor for a table is a percentage between 10 and 100. 100
  (complete packing) is the default.

Click the *Code* tab to continue.

.. image:: images/materialized_view_code.png
    :alt: Materialized view dialog definition tab
    :align: center

Use the text editor field in the *Code* tab to provide the query that will
populate the materialized view. Please note that updating the definition of existing
materialized view would result in loss of Parameter(Table, Toast), Security(Privileges & Security labels),
Indexes and other dependent objects.

Click the *Parameter* tab to continue.

.. image:: images/materialized_view_parameter.png
    :alt: Materialized view dialog parameter tab
    :align: center

Use the tabs nested inside the *Parameter* tab to specify VACUUM and ANALYZE
thresholds; use the *Table* tab and the *Toast Table* tab to customize values
for the table and the associated toast table. To change the default values:

* Move the *Custom auto-vacuum?* switch to the *Yes* position to perform custom
  maintenance on the materialized view and to select values in the
  *Vacuum table*. The *Vacuum Table* provides default values for maintenance
  operations.
* Changing *Autovacuum enabled?* to *Not set* will reset autovacuum_enabled.

Click the *Security* tab to continue.

.. image:: images/materialized_view_security.png
    :alt: Materialized view dialog security tab
    :align: center

Use the *Security* tab to assign privileges and define security labels.

Use the *Privileges* panel to assign privileges to a role. Click the *Add* icon
(+) to set privileges for the materialized view:

* Select the name of the role from the drop-down listbox in the *Grantee* field.
* Click inside the *Privileges* field. Check the boxes to the left of one or
  more privileges to grant the selected privilege to the specified user.
* The current user, who is the default grantor for granting the privilege, is displayed in the *Grantor* field.

Click the *Add* icon (+) to assign additional privileges; to discard a
privilege, click the trash icon to the left of the row and confirm deletion in
the *Delete Row* popup.

Use the *Security Labels* panel to define security labels applied to the
materialized view. Click the *Add* icon (+) to add each security label
selection:

* Specify a security label provider in the *Provider* field. The named provider
  must be loaded and must consent to the proposed labeling operation.
* Specify a a security label in the *Security Label* field. The meaning of a
  given label is at the discretion of the label provider. PostgreSQL places no
  restrictions on whether or how a label provider must interpret security
  labels; it merely provides a mechanism for storing them.

Click the *Add* icon (+) to assign additional security labels; to discard a
security label, click the trash icon to the left of the row and confirm deletion
in the *Delete Row* popup.

Click the *SQL* tab to continue.

Your entries in the *Materialized View* dialog generate a SQL command (see an
example below). Use the *SQL* tab for review; revisit or switch tabs to make any
changes to the SQL command.

Example
*******

The following is an example of the sql command generated by user selections in
the *Materialized View* dialog:

.. image:: images/materialized_view_sql.png
    :alt: Materialized view dialog sql tab
    :align: center

The example shown creates a query named *new_hires* that stores the result of
the displayed query in the *pg_default* tablespace.

* Click the *Info* button (i) to access online help.
* Click the *Save* button to save work.
* Click the *Close* button to exit without saving work.
* Click the *Reset* button to restore configuration parameters.
