CREATE PACKAGE

Function

CREATE PACKAGE creates a package.

Precautions

The package can be used only in centralized databases and cannot be used in distributed databases.
The functions or stored procedures declared in the package specification must be defined in the package body.
During instantiation, the stored procedure with commit or rollback cannot be invoked.
Package functions cannot be invoked in triggers.
Variables in a package cannot be directly used in external SQL statements.
Private variables and stored procedures in a package cannot be invoked outside the package.
Usage that other stored procedures do not support are not supported. For example, if commit or rollback cannot be invoked in a function, commit or rollback cannot be invoked in the function of a package.
The name of a schema cannot be the same as that of a package.
Only A-version stored procedures and function definitions are supported.
Variables with the same name in a package, including parameters with the same name in a package, are not supported.
The global variables in a package are at the session level. The variables in packages cannot be shared in different sessions.
When a function of an autonomous transaction is called in a package, the cursor variables in the package and recursive functions that use the cursor variables in the package are not allowed.
The package does not declare the ref cursor variables.
The default permission on a package is SECURITY INVOKER. To change the default permission to SECURITY DEFINER, set the GUC parameter behavior_compat_options to 'plsql_security_definer'.
A user granted with the CREATE ANY PACKAGE permission can create packages in the public and user schemas.
If the name of a package to be created contains special characters, the special characters cannot contain spaces. You are advised to set the GUC parameter behavior_compat_options to “skip_insert_gs_source”. Otherwise, an error may occur.

Syntax

CREATE PACKAGE SPECIFICATION

CREATE [ OR REPLACE ] PACKAGE [ schema. ] package_name
    [ invoker_rights_clause ] { IS | AS } item_list_1 END package_name;

invoker_rights_clause can be declared as AUTHID DEFINER or AUTHID CURRENT_USER, which indicate the definer permission and invoker permission, respectively.
item_list_1 can be a declared variable, stored procedure, or function.

The package specification declares public variables, functions, and exceptions in a package, which can be invoked by external functions or stored procedures. It can only declare stored procedures and functions but cannot define them.

CREATE PACKAGE BODY
```
CREATE [ OR REPLACE ] PACKAGE BODY [ schema. ] package_name
    { IS | AS } declare_section [ initialize_section ] END package_name;
```
The package body defines private variables and functions in a package. If a variable or function is not declared by the package specification, it is a private variable or function.
The package body also has an initialization part to initialize the package. For details, see the example.

Examples

CREATE PACKAGE SPECIFICATION

CREATE OR REPLACE PACKAGE emp_bonus IS
var1 int:=1;-- Public variable
var2 int:=2;
PROCEDURE testpro1(var3 int);-- Public stored procedure, which can be called by external systems.
END emp_bonus;
/

CREATE PACKAGE BODY

drop table if exists test1;
create or replace package body emp_bonus is
var3 int:=3;
var4 int:=4;
procedure testpro1(var3 int)
is
begin
create table if not exists test1(col1 int);
insert into test1 values(var1);
insert into test1 values(var4);
end;
begin: --The instantiation starts.
var4:=9;
testpro1(var4);
end emp_bonus;
/

Example of ALTER PACKAGE OWNER

-- Change the owner of PACKAGE emp_bonus to omm.
ALTER PACKAGE emp_bonus OWNER TO omm;

Example of calling a package

call emp_bonus.testpro1(1); -- Use **call** to call the stored procedure of a package.
select emp_bonus.testpro1(1); -- Use **select** to call the stored procedure of a package.
--Call the stored procedure of a package in an anonymous block.
begin
emp_bonus.testpro1(1);
end;
/