"只可遠(yuǎn)觀不可褻玩也" 在數(shù)據(jù)庫的世界里你只能看不能動。如果實(shí)現(xiàn)？那就是視圖（Views）
如何創(chuàng)建、更新和刪除視圖。
創(chuàng)建視圖
視圖是基于 SQL 語句的結(jié)果集的可視化的表。
視圖包含行和列，就像一個真實(shí)的表。視圖中的字段就是來自一個或多個數(shù)據(jù)庫中的真實(shí)的表中的字段。
您可以向視圖添加 SQL 函數(shù)、WHERE 以及 JOIN 語句，也可以呈現(xiàn)數(shù)據(jù)，就像這些數(shù)據(jù)來自于某個單一的表一樣。
注意視圖可以連接多個庫及庫中的多個表及表中的多個字段。
語法
CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition
樣例
create view v_bom_zy as
select distinct s.ID,
s.DATAID,
(s.D_itemCode || '') as CODE_V,
(s.D_objectName || '') as NAME_V,
'' as SPECIFICATION_V,
'' as MODEL_V,
'' as DEPT_V,
'' as UNIT_V,
(s.D_itemCode || '') as UNIQUEKEY_V,
'F30D29D602BB4898ABE2F2FB0C894955' as MODELID_V
from ZZJ_TABLE248 s
where s.VERSIONSTATUS = '1'
union all
select distinct s.ID,
s.DATAID,
(s.D_itemCode || '') as CODE_V,
(s.D_objectName || '') as NAME_V,
'' as SPECIFICATION_V,
'' as MODEL_V,
'' as DEPT_V,
'' as UNIT_V,
(s.D_itemCode || '') as UNIQUEKEY_V,
'6DF02A65B4914E2B9692F27A40D13A3F' as MODELID_V
from ZZJ_TABLE01248 s
where s.VERSIONSTATUS = '1';
更新視圖 create or replace view
語法：
create or repalce view 視圖名稱 as select 列名 from 表名 where 條件
create or replace view v_bom_zy as
select distinct s.ID,
s.DATAID,
(s.D_itemCode || '') as CODE_V,
(s.D_objectName || '') as NAME_V,
'' as SPECIFICATION_V,
'' as MODEL_V,
'' as DEPT_V,
'' as UNIT_V,
(s.D_itemCode || '') as UNIQUEKEY_V,
'F30D29D602BB4898ABE2F2FB0C894955' as MODELID_V
from ZZJ_TABLE248 s
where s.VERSIONSTATUS = '1'
union all
select distinct s.ID,
s.DATAID,
(s.D_itemCode || '') as CODE_V,
(s.D_objectName || '') as NAME_V,
'' as SPECIFICATION_V,
'' as MODEL_V,
'' as DEPT_V,
'' as UNIT_V,
(s.D_itemCode || '') as UNIQUEKEY_V,
'6DF02A65B4914E2B9692F27A40D13A3F' as MODELID_V
from ZZJ_TABLE01248 s
where s.VERSIONSTATUS = '1';
刪除視圖
語法
drop view 視圖名稱
樣例
drop view v_bom_zy
