DROP FUNCTION

Description

Deletes a function.

This function is for internal use only and not available to users.

Precautions

• If a function involves operations on temporary tables, DROP FUNCTION cannot be used.
• Only the function owner or a user granted with the DROP permission can run the DROP FUNCTION command. The system administrator has this permission by default.

Syntax

DROP FUNCTION [ IF EXISTS ] function_name 
[ ( [ {[ argname ] [ argmode ] argtype} [, ...] ] ) [ CASCADE | RESTRICT ] ];

Parameters

• IF EXISTS

  Specifies that a notice instead of an error is reported if the specified function does not exist.

• function_name

  Specifies the name of the function to be deleted.

  Value range: an existing function name

• argmode

  Specifies the parameter mode of the function.

• argname

  Specifies the parameter name of the function.

• argtype

  Specifies the parameter type of the function.

• CASCADE | RESTRICT
  • CASCADE: automatically deletes the objects that depend on the function.
  • RESTRICT: refuses to delete the function if any objects depend on it. This is the default action.

Examples

• Delete the list of parameters that can be omitted when a function.

  -- Create a function.
  m_db=# CREATE OR REPLACE FUNCTION func_add_sql(integer, integer) RETURNS bigint
  AS 'select $1 + $2;'
  LANGUAGE SQL
  IMMUTABLE
  SHIPPABLE
  STRICT
  AUTHID DEFINER
  not fenced
  COST 10000;
  /
  
  -- Delete the function.
  m_db=# DROP FUNCTION func_add_sql;

• Delete a function with the same name.
  If a function with the same name exists, add a parameter list when deleting the function. Otherwise, an error is reported.

  -- Create a function.
  m_db=# CREATE OR REPLACE FUNCTION func_increment_plsql(i integer) RETURNS integer AS $$
  BEGIN
      RETURN i + 1;
  END;
  $$ LANGUAGE plpgsql;
  
  
  -- func_add is an overloaded function.
  m_db=# CREATE OR REPLACE FUNCTION func_add(int) RETURNS int AS $$
  BEGIN
      RETURN $1+10;
  END;
  $$ LANGUAGE PLPGSQL;
  
  -- Delete the function.
  m_db=# DROP FUNCTION func_add(int);
  m_db=# DROP FUNCTION func_add(int,int);

Helpful Links

CREATE FUNCTION