CREATE PROCEDURE
CREATE PROCEDURE
7
SQL - Language Statements
CREATE PROCEDURE
define a new procedure
CREATE [ OR REPLACE ] PROCEDURE
name ( [ [ argmode ] [ argname ] argtype [ { DEFAULT | = } default_expr ] [, ...] ] )
{ LANGUAGE lang_name
| TRANSFORM { FOR TYPE type_name } [, ... ]
| [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER
| SET configuration_parameter { TO value | = value | FROM CURRENT }
| AS 'definition'
| AS 'obj_file', 'link_symbol'
} ...
Description
CREATE PROCEDURE defines a new procedure.
CREATE OR REPLACE PROCEDURE will either create a
new procedure, or replace an existing definition.
To be able to define a procedure, the user must have the
USAGE privilege on the language.
If a schema name is included, then the procedure is created in the
specified schema. Otherwise it is created in the current schema.
The name of the new procedure must not match any existing procedure or function
with the same input argument types in the same schema. However,
procedures and functions of different argument types can share a name (this is
called overloading).
To replace the current definition of an existing procedure, use
CREATE OR REPLACE PROCEDURE. It is not possible
to change the name or argument types of a procedure this way (if you
tried, you would actually be creating a new, distinct procedure).
When CREATE OR REPLACE PROCEDURE is used to replace an
existing procedure, the ownership and permissions of the procedure
do not change. All other procedure properties are assigned the
values specified or implied in the command. You must own the procedure
to replace it (this includes being a member of the owning role).
The user that creates the procedure becomes the owner of the procedure.
To be able to create a procedure, you must have USAGE
privilege on the argument types.
Parameters
name
The name (optionally schema-qualified) of the procedure to create.
argmode
The mode of an argument: IN,
INOUT, or VARIADIC. If omitted,
the default is IN. (OUT
arguments are currently not supported for procedures. Use
INOUT instead.)
argname
The name of an argument.
argtype
The data type(s) of the procedure's arguments (optionally
schema-qualified), if any. The argument types can be base, composite,
or domain types, or can reference the type of a table column.
Depending on the implementation language it might also be allowed
to specify pseudo-types
such as cstring.
Pseudo-types indicate that the actual argument type is either
incompletely specified, or outside the set of ordinary SQL data types.
The type of a column is referenced by writing
table_name.column_name%TYPE.
Using this feature can sometimes help make a procedure independent of
changes to the definition of a table.
default_expr
An expression to be used as default value if the parameter is
not specified. The expression has to be coercible to the
argument type of the parameter.
All input parameters following a
parameter with a default value must have default values as well.
lang_name
The name of the language that the procedure is implemented in.
It can be sql, c,
internal, or the name of a user-defined
procedural language, e.g. plpgsql. Enclosing the
name in single quotes is deprecated and requires matching case.
TRANSFORM { FOR TYPE type_name } [, ... ] }
Lists which transforms a call to the procedure should apply. Transforms
convert between SQL types and language-specific data types;
see . Procedural language
implementations usually have hardcoded knowledge of the built-in types,
so those don't need to be listed here. If a procedural language
implementation does not know how to handle a type and no transform is
supplied, it will fall back to a default behavior for converting data
types, but this depends on the implementation.
EXTERNAL SECURITY INVOKER
EXTERNAL SECURITY DEFINER
SECURITY INVOKER indicates that the procedure
is to be executed with the privileges of the user that calls it.
That is the default. SECURITY DEFINER
specifies that the procedure is to be executed with the
privileges of the user that owns it.
The key word EXTERNAL is allowed for SQL
conformance, but it is optional since, unlike in SQL, this feature
applies to all procedures not only external ones.
A SECURITY DEFINER procedure cannot execute
transaction control statements (for example, COMMIT
and ROLLBACK, depending on the language).
configuration_parameter
value
The SET clause causes the specified configuration
parameter to be set to the specified value when the procedure is
entered, and then restored to its prior value when the procedure exits.
SET FROM CURRENT saves the value of the parameter that
is current when CREATE PROCEDURE is executed as the value
to be applied when the procedure is entered.
If a SET clause is attached to a procedure, then
the effects of a SET LOCAL command executed inside the
procedure for the same variable are restricted to the procedure: the
configuration parameter's prior value is still restored at procedure exit.
However, an ordinary
SET command (without LOCAL) overrides the
SET clause, much as it would do for a previous SET
LOCAL command: the effects of such a command will persist after
procedure exit, unless the current transaction is rolled back.
If a SET clause is attached to a procedure, then
that procedure cannot execute transaction control statements (for
example, COMMIT and ROLLBACK,
depending on the language).
See and
for more information about allowed parameter names and values.
definition
A string constant defining the procedure; the meaning depends on the
language. It can be an internal procedure name, the path to an
object file, an SQL command, or text in a procedural language.
It is often helpful to use dollar quoting (see ) to write the procedure definition
string, rather than the normal single quote syntax. Without dollar
quoting, any single quotes or backslashes in the procedure definition must
be escaped by doubling them.
obj_file, link_symbol
This form of the AS clause is used for
dynamically loadable C language procedures when the procedure name
in the C language source code is not the same as the name of
the SQL procedure. The string obj_file is the name of the shared
library file containing the compiled C procedure, and is interpreted
as for the command. The string
link_symbol is the
procedure's link symbol, that is, the name of the procedure in the C
language source code. If the link symbol is omitted, it is assumed
to be the same as the name of the SQL procedure being defined.
When repeated CREATE PROCEDURE calls refer to
the same object file, the file is only loaded once per session.
To unload and
reload the file (perhaps during development), start a new session.
Notes
See for more details on function
creation that also apply to procedures.
Use to execute a procedure.
Examples
CREATE PROCEDURE insert_data(a integer, b integer)
LANGUAGE SQL
AS $$
INSERT INTO tbl VALUES (a);
INSERT INTO tbl VALUES (b);
$$;
CALL insert_data(1, 2);
Compatibility
A CREATE PROCEDURE command is defined in the SQL
standard. The PostgreSQL version is similar but
not fully compatible. For details see
also .
See Also