同义词是数据库对象的一个别名，经常用于简化对象访问和提高对象访问的安全性。在使用同义词时，HALO数据库将它翻译成对应对象的名字。与视图类似，同义词并不占用实际存储空间，只有在数据字典中保存了同义词的定义。本文将简单展示一下Halo数据库中新增的同义词相关功能。

一、语法定义

create synonym synonym_name for schema_name.object_name;

二、相关方法演示

2.1、view

视图同义词的创建与调用。

create view oracle.vb as select * from dual;

create synonym syn_b for oracle.vb;

select * from syn_b;

drop synonym syn_b;

2.2、table

表同义词的创建与调用。

create table oracle.tc(a int);

create synonym syn_c for oracle.tc;

select * from syn_c;

insert into syn_c values(1);

select * from syn_c;

drop synonym syn_c;

2.3、procedure

存储过程同义词创建与调用。

create procedure oracle.protestd

as 

begin

raise notice 'oracle.protestd';

end;

/

create synonym syn_d for oracle.protestd;

call syn_d;

drop synonym syn_d;

2.4、function

函数同义词的创建与调用。

create function oracle.ftestf(a int,b int)

return int

as begin

return a + b;

end;

/

create synonym syn_f for oracle.ftestf;

select syn_f(25,26);

drop synonym syn_f;

2.5、sequence

序列同义词的创建与调用。

CREATE  SEQUENCE oracle.seq_truck_num MINVALUE 1 

MAXVALUE 9223372036854775807 

INCREMENT BY 1 

START with 5258752  

CACHE 20;

create or replace SYNONYM sy_car_seq_truck_num for oracle.seq_truck_num;

select sy_car_seq_truck_num.nextval from dual;

drop synonym sy_car_seq_truck_num;

2.6、package

包的同义词的创建与调用。

CREATE OR REPLACE PACKAGE pkg_a AS

FUNCTION f_test( f_a IN INTEGER , f_b IN INTEGER ) RETURN INTEGER;

PROCEDURE pro_test;

END pkg_a;

/

CREATE OR REPLACE PACKAGE BODY pkg_a AS

FUNCTION f_test( f_a IN INTEGER , f_b IN INTEGER )

RETURN INTEGER

AS

f_c INTEGER;

BEGIN 

f_c := f_a + f_b;

RETURN f_c;

END f_test;

PROCEDURE pro_test

AS 

a INTEGER;

BEGIN

a:= pkg_a.f_test(12,13);

RAISE NOTICE 'pkg_a.f_test(12,13) = %',a; 

END pro_test; 

END pkg_a;

/

-- 创建package同义词 

create synonym pkggg for pkg_a;

-- 测试调用函数/存储过程

DECLARE 

  a INTEGER;

BEGIN

  pkggg.pro_test();

  a:=pkggg.f_test(10,13);

  RAISE NOTICE 'a : %',a;

END;

/

drop synonym pkggg;

drop package pkg_a;

好了，至此关于Halo数据库同义词的功能就简单演示完毕了，如文中存在问题，欢迎指正，非常感谢！