[SPARK-28789][DOCS][SQL] Document ALTER DATABASE command

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docs/sql-ref-syntax-ddl-alter-database.md

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   See the License for the specific language governing permissions and
   limitations under the License.
 ---
+### Description
+You can alter metadata associated with a database by setting `DBPROPERTIES`.  The specified property
+values override any existing value with the same property name. Please note that the usage of 
+`SCHEMA` and `DATABASE` are interchangable and one can be used in place of the other. An error message
+is issued if the database is not found in the system. This command is mostly used to record the metadata
+for a database and may be used for auditing purposes.
 
-**This page is under construction**
+### Syntax
+{% highlight sql %}
+ALTER {DATABASE | SCHEMA} database_name SET DBPROPERTIES (propery_name=property_value, ...);
+{% endhighlight %}
+
+### Parameters
+<dl>
+  <dt><code><em>database_name</em></code></dt>
+  <dd>Specifies the name of the database to be altered.</dd>
+</dl>
+
+### Examples
+{% highlight sql %}
+-- Creates a database named `inventory`.
+CREATE DATABASE inventory;
+
+-- Alters the database to set properties `Edited-by` and `Edit-date`.
+ALTER DATABASE inventory SET DBPROPERTIES ('Edited-by' = 'John', 'Edit-date' = '01/01/2001');
+
+-- Verify that properties are set.
+DESCRIBE DATABASE EXTENDED inventory;
+
+   +-------------------------+--------------------------------------------+
+   |database_description_item|database_description_value                  |
+   +-------------------------+--------------------------------------------+
+   |Database Name            |inventory                                   |
+   |Description              |                                            |
+   |Location                 |file:/temp/spark-warehouse/inventory.db     |
+   |Properties               |((Edit-date,01/01/2001), (Edited-by,John))  |
+   +-------------------------+--------------------------------------------+
+{% endhighlight %}
+
+### Related Statements
+- [DESCRIBE DATABASE](sql-ref-syntax-aux-describe-database.html)