DROP FUNCTION

Capella Operational

reference

The DROP FUNCTION statement enables you to delete a user-defined function.

Prerequisites

To execute this statement, your client must have necessary privileges depending on your cluster access credential type and whether the function is global or scoped.

Credential Type Function Type Privilege

Credential Type	Function Type	Privilege
Basic	Global or scoped	`Write`
Advanced	Global	`Global Function Manage`
Advanced	Scoped	`Query Manage`

Basic

Global or scoped

Write

Advanced

Global

Global Function Manage

Advanced

Scoped

Query Manage

Syntax

drop-function ::= 'DROP' 'FUNCTION' function ( 'IF' 'EXISTS' )?

function

Function Name

function ::= ( namespace ':' ( bucket '.' scope '.' )? )? identifier

The name of the function. This is usually an unqualified identifier, such as func1 or `func-1`. In this case, the path to the function is determined by the current query context.

To delete a global function in a particular namespace, the function name must be a qualified identifier with a namespace, such as default:func1. Similarly, to delete a scoped function in a particular scope, the function name must be a qualified identifier with the full path to a scope, such as default:`travel-sample`.inventory.func1. For more information, see Global Functions and Scoped Functions.

The name of a user-defined function is case-sensitive, unlike that of a built-in function. You must delete the user-defined function using the same case that was used when it was created.

IF EXISTS Clause

The optional IF EXISTS clause enables the statement to complete successfully when the specified function does not exist.

When the function does not exist within the specified context: ^[1]

If this clause is not present, an error is generated.
If this clause is present, the statement does nothing and completes without error.

Usage

When you drop a user-defined function whose definition is stored in a JavaScript library, the JavaScript library and function on which the user-defined function depended are not deleted. This enables you to create a new user-defined function with a different name, or a different number of parameters, using the same JavaScript library and function.

To change or delete a JavaScript library or the JavaScript function code, see Create a JavaScript Library.

When you drop a SQL++ managed JavaScript function, the associated JavaScript function code is also deleted.

Examples

To try the examples in this section, set the query context to the inventory scope in the travel sample dataset. For more information, see Query Context.

Example 1. Drop an inline function

This statement deletes an inline function called celsius.

DROP FUNCTION celsius;

You can run the following query to check that the function is no longer available.

SELECT * FROM system:functions;

Example 2. Drop a SQL++ managed JavaScript function

This statement deletes a SQL++ managed JavaScript function called add100.

DROP FUNCTION add100 IF EXISTS;

You can run the following query to check that the function is no longer available.

SELECT * FROM system:functions;

Example 3. Drop a UDF library function

These statements delete two UDF library functions:

A function called geohash, which depends on the JavaScript encodeGeoHash function in the geohash-js library;
A function called adjacent, which depends on the JavaScript calculateAdjacent function in the geohash-js library.

DROP FUNCTION geohash;

DROP FUNCTION adjacent;

1. In other words, you’re dropping a global function, and the function does not exist within the specified namespace; or, you’re dropping a scoped function, and the function does not exist within the specified scope.