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更新特定視圖中的任何值後,MySQL 是否會更新基底表及其關聯視圖(如果有)中的相同值?

WBOY
WBOY轉載
2023-08-24 09:37:021338瀏覽

更新特定视图中的任何值后,MySQL 是否会更新基表及其关联视图(如果有)中的相同值?

Yes, MySQL will update the value, if it is updated in a view, in the base table as well as in its associated views. To illustrate it we are taking the example of table Student_info having the following data −

mysql> Select * from student_info;
+------+---------+------------+------------+
| id   | Name    | Address    | Subject    |
+------+---------+------------+------------+
| 101  | YashPal | Amritsar   | History    |
| 105  | Gaurav  | Chandigarh | Literature |
| 125  | Raman   | Shimla     | Computers  |
| NULL | Ram     | Jhansi     | Computers  |
+------+---------+------------+------------+
4 rows in set (0.00 sec)

以下是基於表格'Student_info' 建立的視圖'Info'

mysql> Select * from Info;
+------+---------+------------+
| Id   | Name    | Subject    |
+------+---------+------------+
| 101  | YashPal | History    |
| 105  | Gaurav  | Literature |
| 125  | Raman   | Computers  |
| NULL | Ram     | Computers  |
+------+---------+------------+
4 rows in set (0.00 sec)

現在在下面的查詢中,我們將更新視圖'Info' −

mysql> Update info set id = 130 where Name = 'Ram';
Query OK, 1 row affected (0.88 sec)

mysql> Select * from Info;
+------+---------+------------+
| Id   | Name    | Subject    |
+------+---------+------------+
| 101  | YashPal | History    |
| 105  | Gaurav  | Literature |
| 125  | Raman   | Computers  |
| 130  | Ram     | Computers  |
+------+---------+------------+
4 rows in set (0.00 sec)

上述結果集顯示檢視'Info' 已更新。

mysql> Select * from student_info;
+------+---------+------------+------------+
| id   | Name    | Address    | Subject    |
+------+---------+------------+------------+
| 101  | YashPal | Amritsar   | History    |
| 105  | Gaurav  | Chandigarh | Literature |
| 125  | Raman   | Shimla     | Computers  |
| 130  | Ram     | Jhansi     | Computers  |
+------+---------+------------+------------+
4 rows in set (0.00 sec)

上面的結果集顯示,當我們更新名為'info'的視圖時,基本表也會被更新。

下面是基於視圖'info'創建的名為'info_less'的視圖,當我們更新視圖'info'時,它也會被更新。

mysql> Select * from info_less;
+------+-------+-----------+
| Id   | Name  | Subject   |
+------+-------+-----------+
| 125  | Raman | Computers |
| 130  | Ram   | Computers |
+------+-------+-----------+
2 rows in set (0.00 sec)

以上是更新特定視圖中的任何值後,MySQL 是否會更新基底表及其關聯視圖(如果有)中的相同值?的詳細內容。更多資訊請關注PHP中文網其他相關文章!

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