CREATE PACKAGE

Description

Creates a package.

Precautions

• 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 called.
• When a stored procedure is created, a write lock is added only to the CREATE stored procedure or package, and a read lock is added only to the functions and packages on which the functions depend during compilation and execution.
• Package functions cannot be called in triggers.
• Variables in a package cannot be directly used in external SQL statements.
• Private variables and stored procedures in a package cannot be called outside the package.
• Usage that other stored procedures do not support are not supported. For example, if commit or rollback cannot be called in a function, commit or rollback cannot be called 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.
• When a package is created, it depends on an undefined object. If behavior_compat_options is set to 'plpgsql_dependency', the creation can be executed and a warning message is displayed. If behavior_compat_options is not set to 'plpgsql_dependency', the creation cannot be executed.
• If a view directly depends on an A-compatible function in a package and the behavior_compat_options parameter is set to 'plpgsql_dependency', the view can be accessed if the package is created again. However, if the behavior_compat_options parameter is not set to 'plpgsql_dependency', the view cannot be accessed.
• When you create a package function, the default parameter value cannot contain variables.
• The package specification in PG_OBJECT is set to 'S', and the package body in PG_OBJECT is set to 'B'. When a created package object becomes invalid, you can use the VALID column in PG_OBJECT to search for the OID of the invalid package object and run ALTER PACKAGE PKG_NAME COMPILE; to recompile the package to make it valid.
• When creating a function in a package, if the function name is in the schema.func or package.func format, only the func name is obtained. The schema declaration or package declaration is invalid. To disable this behavior by default, set the GUC parameter behavior_compat_options to 'forbid_package_function_with_prefix'.

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 caller permission, respectively.
  item_list_1 can be a declared variable, stored procedure, or function.

  PACKAGE SPECIFICATION (header) declares public variables, functions, and exceptions in a package, which can be called 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

• Example of CREATE PACKAGE SPECIFICATION

  gaussdb=# 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;
  /

• Example of CREATE PACKAGE BODY

  gaussdb=# drop table if exists test1;
  gaussdb=# 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.
  gaussdb=# ALTER PACKAGE emp_bonus OWNER TO omm;

• Example of calling a package

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