"只可远观不可亵玩也" 在数据库的世界里你只能看不能动。如果实现?那就是视图(Views)
如何创建、更新和删除视图。
创建视图
视图是基于 SQL 语句的结果集的可视化的表。
视图包含行和列,就像一个真实的表。视图中的字段就是来自一个或多个数据库中的真实的表中的字段。
您可以向视图添加 SQL 函数、WHERE 以及 JOIN 语句,也可以呈现数据,就像这些数据来自于某个单一的表一样。
注意视图可以连接多个库及库中的多个表及表中的多个字段。
语法
CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition
样例
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';
更新视图 create or replace view
语法:
create or repalce view 视图名称 as select 列名 from 表名 where 条件
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';
删除视图
语法
drop view 视图名称
样例
drop view v_bom_zy