第七色在线视频,2021少妇久久久久久久久久,亚洲欧洲精品成人久久av18,亚洲国产精品特色大片观看完整版,孙宇晨将参加特朗普的晚宴

<style id="fq9r1"></style>

                        課程
                    
                        /數(shù)據(jù)庫
                        
                            /MySQL
                        
                        /與MySQL的零距離接觸

只刪除外鍵約束的名字不能直接刪除外鍵約束吧，索引一起刪才能徹底刪除。？？？？

.............

qq_簡簡單單_119

2018-06-07

源自：與MySQL的零距離接觸 3-7

關(guān)注問題我要回答

2738

操作

收起

5 回答

葉0528 回答被采納 +2 積分
2018-06-11

1、查看表結(jié)構(gòu),有外鍵

2、查看INDEXES，有外鍵索引

3、刪除外鍵，查看表結(jié)構(gòu)發(fā)現(xiàn)沒有外鍵，查看索引發(fā)現(xiàn)外鍵索引還在。

沒有發(fā)現(xiàn)你這種情況：

“我只刪除名字查看表結(jié)構(gòu)時(shí)還是顯示有外鍵?。?？？？ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?”

0 回復(fù) 有任何疑惑可以回復(fù)我~

#1

qq_簡簡單單_119 提問者

非常感謝！

2018-06-14 回復(fù) 有任何疑惑可以回復(fù)我~

慕移動(dòng)9181930
2022-03-25

view.getId()來判斷直接使用快捷鍵提示就好了 ?免得自己拼寫錯(cuò)誤。

0 回復(fù) 有任何疑惑可以回復(fù)我~

qq_簡簡單單_119 提問者
2018-06-14

我刪了名字? 表結(jié)構(gòu)中PID列的key還是MUL

0 回復(fù) 有任何疑惑可以回復(fù)我~

#1

索引沒有刪。PRI主鍵約束； UNI唯一約束； MUL可以重復(fù)。

2018-06-19 回復(fù) 有任何疑惑可以回復(fù)我~

#2

mysql中如何設(shè)置某字段Key 為MUL：加個(gè)索引INDEX https://blog.csdn.net/chenxieyy/article/details/70241382

2018-06-19 回復(fù) 有任何疑惑可以回復(fù)我~

葉0528
2018-06-11

mysql>?SHOW?CREATE?TABLE?tdb_goods;
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------------------+
|?Table?????|?Create?Table






?????????????????????????????????????|
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------------------+
|?tdb_goods?|?CREATE?TABLE?`tdb_goods`?(
??`goods_id`?smallint(5)?unsigned?NOT?NULL?AUTO_INCREMENT,
??`goods_name`?varchar(150)?NOT?NULL,
??`cate_id`?smallint(5)?unsigned?NOT?NULL,
??`brand_id`?smallint(5)?unsigned?NOT?NULL,
??`goods_price`?decimal(15,3)?unsigned?NOT?NULL?DEFAULT?'0.000',
??`is_show`?tinyint(1)?NOT?NULL?DEFAULT?'1',
??`is_saleoff`?tinyint(1)?NOT?NULL?DEFAULT?'0',
??PRIMARY?KEY?(`goods_id`),
??KEY?`brand_id`?(`brand_id`),
??CONSTRAINT?`tdb_goods_ibfk_1`?FOREIGN?KEY?(`brand_id`)?REFERENCES?`tdb_goods_b
rands`?(`brand_id`)
)?ENGINE=InnoDB?AUTO_INCREMENT=24?DEFAULT?CHARSET=utf8?|
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
-------------------------------------+
1?row?in?set?(0.00?sec)

mysql>?SHOW?INDEXES?FROM?tdb_goods\G;
***************************?1.?row?***************************
????????Table:?tdb_goods
???Non_unique:?0
?????Key_name:?PRIMARY
?Seq_in_index:?1
??Column_name:?goods_id
????Collation:?A
??Cardinality:?23
?????Sub_part:?NULL
???????Packed:?NULL
?????????Null:
???Index_type:?BTREE
??????Comment:
Index_comment:
***************************?2.?row?***************************
????????Table:?tdb_goods
???Non_unique:?1
?????Key_name:?brand_id
?Seq_in_index:?1
??Column_name:?brand_id
????Collation:?A
??Cardinality:?23
?????Sub_part:?NULL
???????Packed:?NULL
?????????Null:
???Index_type:?BTREE
??????Comment:
Index_comment:
2?rows?in?set?(0.00?sec)

ERROR:
No?query?specified

mysql>?ALTER?TABLE?tdb_goods?DROP?FOREIGN?KEY?tdb_goods_ibfk_1;
Query?OK,?23?rows?affected?(0.05?sec)
Records:?23??Duplicates:?0??Warnings:?0

mysql>?SHOW?CREATE?TABLE?tdb_goods;
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------+
|?Table?????|?Create?Table





????????????????|
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------+
|?tdb_goods?|?CREATE?TABLE?`tdb_goods`?(
??`goods_id`?smallint(5)?unsigned?NOT?NULL?AUTO_INCREMENT,
??`goods_name`?varchar(150)?NOT?NULL,
??`cate_id`?smallint(5)?unsigned?NOT?NULL,
??`brand_id`?smallint(5)?unsigned?NOT?NULL,
??`goods_price`?decimal(15,3)?unsigned?NOT?NULL?DEFAULT?'0.000',
??`is_show`?tinyint(1)?NOT?NULL?DEFAULT?'1',
??`is_saleoff`?tinyint(1)?NOT?NULL?DEFAULT?'0',
??PRIMARY?KEY?(`goods_id`),
??KEY?`brand_id`?(`brand_id`)
)?ENGINE=InnoDB?AUTO_INCREMENT=24?DEFAULT?CHARSET=utf8?|
+-----------+-------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
----------------+
1?row?in?set?(0.01?sec)

mysql>?SHOW?INDEXES?FROM?tdb_goods;
+-----------+------------+----------+--------------+-------------+-----------+--
-----------+----------+--------+------+------------+---------+---------------+
|?Table?????|?Non_unique?|?Key_name?|?Seq_in_index?|?Column_name?|?Collation?|?C
ardinality?|?Sub_part?|?Packed?|?Null?|?Index_type?|?Comment?|?Index_comment?|
+-----------+------------+----------+--------------+-------------+-----------+--
-----------+----------+--------+------+------------+---------+---------------+
|?tdb_goods?|??????????0?|?PRIMARY??|????????????1?|?goods_id????|?A?????????|
????????23?|?????NULL?|?NULL???|??????|?BTREE??????|?????????|???????????????|
|?tdb_goods?|??????????1?|?brand_id?|????????????1?|?brand_id????|?A?????????|
????????23?|?????NULL?|?NULL???|??????|?BTREE??????|?????????|???????????????|
+-----------+------------+----------+--------------+-------------+-----------+--
-----------+----------+--------+------+------------+---------+---------------+
2?rows?in?set?(0.00?sec)

mysql>

0 回復(fù) 有任何疑惑可以回復(fù)我~

#1

qq_簡簡單單_119 提問者

你看一下我下一個(gè)回答我的意思是這個(gè) ，搞不懂為什么。

2018-06-14 回復(fù) 有任何疑惑可以回復(fù)我~

葉0528
2018-06-08

只刪除外鍵約束的名字能直接刪除外鍵約束，

但是這個(gè)外鍵的索引還在。

添加外鍵約束的時(shí)候會(huì)自動(dòng)添加其索引。

0 回復(fù) 有任何疑惑可以回復(fù)我~

#1

qq_簡簡單單_119 提問者

我只刪除名字查看表結(jié)構(gòu)時(shí)還是顯示有外鍵?。?？？？

2018-06-08 回復(fù) 有任何疑惑可以回復(fù)我~

舉報(bào)

0/150

提交

取消

與MySQL的零距離接觸

參與學(xué)習(xí) 396758 人
解答問題 3472 個(gè)

本課程涵蓋全部MySQL數(shù)據(jù)庫的基礎(chǔ)，學(xué)習(xí)MySQL數(shù)據(jù)庫的基礎(chǔ)知識(shí)

進(jìn)入課程

只刪除外鍵約束的名字不能直接刪除外鍵約束吧，索引一起刪才能徹底刪除。？？？？

我要回答關(guān)注問題

購課補(bǔ)貼
聯(lián)系客服咨詢優(yōu)惠詳情

幫助反饋 APP下載

慕課網(wǎng)APP
您的移動(dòng)學(xué)習(xí)伙伴

公眾號(hào)

掃描二維碼
關(guān)注慕課網(wǎng)微信公眾號(hào)

<strike id="e9uzs"><rt id="e9uzs"></rt></strike>