NAME

       CREATE_PROCEDURE - define a new procedure

SYNOPSIS

       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'
           | sql_body
         } ...

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.

       Refer to Section 38.4 for further information on writing procedures.

PARAMETERS

       name
           The name (optionally schema-qualified) of the procedure to create.

       argmode
           The mode of an argument: IN, OUT, INOUT, or VARIADIC. If omitted, the default is IN.

       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. The default is sql if sql_body is
           specified. 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 CREATE TRANSFORM (CREATE_TRANSFORM(7)). 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 SET(7) and Chapter 20 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 Section 4.1.2.4) 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 LOAD 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.

       sql_body
           The body of a LANGUAGE SQL procedure. This should be a block

               BEGIN ATOMIC
                 statement;
                 statement;
                 ...
                 statement;
               END

           This is similar to writing the text of the procedure body as a string constant (see definition
           above), but there are some differences: This form only works for LANGUAGE SQL, the string constant
           form works for all languages. This form is parsed at procedure definition time, the string constant
           form is parsed at execution time; therefore this form cannot support polymorphic argument types and
           other constructs that are not resolvable at procedure definition time. This form tracks dependencies
           between the procedure and objects used in the procedure body, so DROP ... CASCADE will work
           correctly, whereas the form using string literals may leave dangling procedures. Finally, this form
           is more compatible with the SQL standard and other SQL implementations.

NOTES

       See CREATE FUNCTION (CREATE_FUNCTION(7)) for more details on function creation that also apply to
       procedures.

       Use CALL(7) to execute a procedure.

EXAMPLES

           CREATE PROCEDURE insert_data(a integer, b integer)
           LANGUAGE SQL
           AS $$
           INSERT INTO tbl VALUES (a);
           INSERT INTO tbl VALUES (b);
           $$;

       or

           CREATE PROCEDURE insert_data(a integer, b integer)
           LANGUAGE SQL
           BEGIN ATOMIC
             INSERT INTO tbl VALUES (a);
             INSERT INTO tbl VALUES (b);
           END;

       and call like this:

           CALL insert_data(1, 2);

COMPATIBILITY

       A CREATE PROCEDURE command is defined in the SQL standard. The PostgreSQL implementation can be used in a
       compatible way but has many extensions. For details see also CREATE FUNCTION (CREATE_FUNCTION(7)).

SEE ALSO

       ALTER PROCEDURE (ALTER_PROCEDURE(7)), DROP PROCEDURE (DROP_PROCEDURE(7)), CALL(7), CREATE FUNCTION
       (CREATE_FUNCTION(7))