DROP VIEW

Removes a view from the database. Multiple views can be dropped with a single DROP VIEW command. This command isn't reversible.

Syntax

DROP VIEW [ IF EXISTS ] name [, ... ] [ CASCADE | RESTRICT ] 

Parameters

IF EXISTS

Clause that indicates that if the specified view doesn’t exist, the command should make no changes and return a message that the view doesn't exist, rather than terminating with an error.

This clause is useful when scripting, so the script doesn’t fail if DROP VIEW runs against a nonexistent view.

name

Name of the view to be removed.

CASCADE

Clause that indicates to automatically drop objects that depend on the view, such as other views.

To create a view that isn't dependent on other database objects, such as views and tables, include the WITH NO SCHEMA BINDING clause in the view definition. For more information, see CREATE VIEW.

RESTRICT

Clause that indicates not to drop the view if any objects depend on it. This action is the default.

Examples

The following example drops the view called event:

drop view event;

To remove a view that has dependencies, use the CASCADE option. For example, say we start with a table called EVENT. We then create the eventview view of the EVENT table, using the CREATE VIEW command, as shown in the following example:

create view eventview as
select dateid, eventname, catid
from event where catid = 1;

Now, we create a second view called myeventview, that is based on the first view eventview:

create view myeventview as 
select eventname, catid
from eventview where eventname <> ' ';

At this point, two views have been created: eventview and myeventview.

The myeventview view is a child view witheventview as its parent.

To delete the eventview view, the obvious command to use is the following:

drop view eventview;

Notice that if you run this command in this case, you get the following error:

drop view eventview;
ERROR: can't drop view eventview because other objects depend on it
HINT: Use DROP ... CASCADE to drop the dependent objects too.

To remedy this, run the following command (as suggested in the error message):

drop view eventview cascade;

Both eventview and myeventview have now been dropped successfully.

The following example either drops the eventview view if it exists, or does nothing and returns a message if it doesn't:

drop view if exists eventview;