Ubuntu Manpage: DROP_PROCEDURE - remove a procedure

Provided by: postgresql-client-17_17.2-1_amd64

NAME

       DROP_PROCEDURE - remove a procedure

SYNOPSIS

       DROP PROCEDURE [ IF EXISTS ] name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] [, ...]
           [ CASCADE | RESTRICT ]

DESCRIPTION

       DROP PROCEDURE removes the definition of one or more existing procedures. To execute this
       command the user must be the owner of the procedure(s). The argument types to the
       procedure(s) usually must be specified, since several different procedures can exist with
       the same name and different argument lists.

PARAMETERS

       IF EXISTS
           Do not throw an error if the procedure does not exist. A notice is issued in this
           case.

       name
           The name (optionally schema-qualified) of an existing procedure.

       argmode
           The mode of an argument: IN, OUT, INOUT, or VARIADIC. If omitted, the default is IN
           (but see below).

       argname
           The name of an argument. Note that DROP PROCEDURE does not actually pay any attention
           to argument names, since only the argument data types are used to determine the
           procedure's identity.

       argtype
           The data type(s) of the procedure's arguments (optionally schema-qualified), if any.
           See below for details.

       CASCADE
           Automatically drop objects that depend on the procedure, and in turn all objects that
           depend on those objects (see Section 5.15).

       RESTRICT
           Refuse to drop the procedure if any objects depend on it. This is the default.

NOTES

If there is only one procedure of the given name, the argument list can be omitted. Omit
the parentheses too in this case.

In PostgreSQL, it's sufficient to list the input (including INOUT) arguments, because no
two routines of the same name are allowed to share the same input-argument list. Moreover,
the DROP command will not actually check that you wrote the types of OUT arguments
correctly; so any arguments that are explicitly marked OUT are just noise. But writing
them is recommendable for consistency with the corresponding CREATE command.

For compatibility with the SQL standard, it is also allowed to write all the argument data
types (including those of OUT arguments) without any argmode markers. When this is done,
the types of the procedure's OUT argument(s) will be verified against the command. This
provision creates an ambiguity, in that when the argument list contains no argmode
markers, it's unclear which rule is intended. The DROP command will attempt the lookup
both ways, and will throw an error if two different procedures are found. To avoid the
risk of such ambiguity, it's recommendable to write IN markers explicitly rather than
letting them be defaulted, thus forcing the traditional PostgreSQL interpretation to be
used.

The lookup rules just explained are also used by other commands that act on existing
procedures, such as ALTER PROCEDURE and COMMENT ON PROCEDURE.

EXAMPLES

       If there is only one procedure do_db_maintenance, this command is sufficient to drop it:

           DROP PROCEDURE do_db_maintenance;

       Given this procedure definition:

           CREATE PROCEDURE do_db_maintenance(IN target_schema text, OUT results text) ...

       any one of these commands would work to drop it:

           DROP PROCEDURE do_db_maintenance(IN target_schema text, OUT results text);
           DROP PROCEDURE do_db_maintenance(IN text, OUT text);
           DROP PROCEDURE do_db_maintenance(IN text);
           DROP PROCEDURE do_db_maintenance(text);
           DROP PROCEDURE do_db_maintenance(text, text);  -- potentially ambiguous

       However, the last example would be ambiguous if there is also, say,

           CREATE PROCEDURE do_db_maintenance(IN target_schema text, IN options text) ...

COMPATIBILITY

       This command conforms to the SQL standard, with these PostgreSQL extensions:

       •   The standard only allows one procedure to be dropped per command.

       •   The IF EXISTS option is an extension.

       •   The ability to specify argument modes and names is an extension, and the lookup rules
           differ when modes are given.