.. _index_dialog:

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`Index Dialog`:index:
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Use the *Index* dialog to create an index on a specified table or materialized
view.

The *Index* dialog organizes the development of a index through the following
dialog tabs: *General* and *Definition*. The *SQL* tab displays the SQL code
generated by dialog selections.

.. image:: images/index_general.png
    :alt: Index dialog general tab
    :align: center

Use the fields in the *General* tab to identify the index:

* Use the *Name* field to add a descriptive name for the index. The name will
  be displayed in the *pgAdmin* tree control.
* Use the drop-down listbox next to *Tablespace* to select the tablespace in
  which the index will reside.
* Store notes about the index in the *Comment* field.

Click the *Definition* tab to continue.

.. image:: images/index_definition.png
    :alt: Index dialog definition tab
    :align: center

Use the fields in the *Definition* tab to define the index:

* Use the drop-down listbox next to *Access Method* to select an index type:

    * Select *btree* to create a B-tree index.  A B-tree index may improve
      performance when managing equality and range queries on data that can be
      sorted into some ordering (the default).
    * Select *hash* to create a hash index.  A hash index may improve
      performance when managing simple equality comparisons.
    * Select *gist* to create a GiST index.  A GiST index may improve
      performance when managing two-dimensional geometric data types and
      nearest-neighbor searches.
    * Select *gin* to create a GIN index.  A GIN index may improve
      performance when managing values with more than one key.
    * Select *spgist* to create a space-partitioned GiST index. A SP-GiST index
      may improve performance when managing non-balanced data structures.
    * Select *brin* to create a BRIN index.  A BRIN index may improve
      performance when managing minimum and maximum values and ranges.

* Use the *Fill Factor* field to specify a fill factor for the index. The fill
  factor specifies how full the selected method will try to fill each index
  page.
* Move the *Unique?* switch to the *Yes* position to check for duplicate values
  in the table when the index is created and when data is added. The default is
  *No*.
* Move the *Clustered?* switch to the *Yes* position to instruct the server to
  cluster the table.
* Move the *Concurrent build?* switch to the *Yes* position to build the index
  without taking any locks that prevent concurrent inserts, updates, or deletes
  on the table.
* Use the *Constraint* field to provide a constraint expression; a constraint
  expression limits the entries in the index to those rows that satisfy the
  constraint.

Use the context-sensitive fields in the *Columns* panel to specify which
column(s) the index queries. Click the *Add* icon (+) to add a column:

* Use the drop-down listbox in *Column* field to select the name of the column
  rom the table.
* If enabled, use the drop-down listbox to select an available *Operator class*
  to specify the type of action performed on the column.
* If enabled, move the *Sort order* switch to specify the sort order:

    * Select *ASC* to specify an ascending sort order (the default);
    * Select *DESC* to specify a descending sort order.

* If enabled, move the *Nulls* switch to specify the sort order of nulls:

    * Select *First* to specify nulls sort before non-nulls;
    * Select *Last* to specify nulls sort after non-nulls (the default).

* Use the drop-down listbox in the *Collation* field to select a collation to
  use for the index.

Use *Include columns* field to specify columns for *INCLUDE* clause of the
index. This option is available in Postgres 11 and later.

Click the *SQL* tab to continue.

Your entries in the *Index* 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 *Index* dialog:

.. image:: images/index_sql.png
    :alt: Index dialog sql tab
    :align: center

The example shown demonstrates creating an index named *dist_codes* that indexes
the values in the *code* column of the *distributors* table.

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