Microsoft Windows [版本 6.1.7601]
版权所有 (c) 2009 Microsoft Corporation。保留所有权利。
C:/Users/Administrator>net start mysql56
MySQL56 服务正在启动 ..
MySQL56 服务已经启动成功。
C:/Users/Administrator>mysql -u root -p
Enter password: *****
Welcome to the MySQL monitor. Commands end with ; or /g.
Your MySQL connection id is 1
Server version: 5.6.10 MySQL Community Server (GPL)
Type 'help;' or '/h' for help. Type '/c' to clear the buffer.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| bbs |
| book |
| connect |
| db_bbs |
| db_database25 |
| dreamtimenews |
| hibernate |
| hrsystem |
| jeebbs |
| jeecmsv5 |
| meiupic |
| mysql |
| news |
| nmsdb |
| oscommerce |
| performance_schema |
| sakila |
| test |
| vote |
| world |
+--------------------+
21 rows in set (0.23 sec)
mysql> use test;
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| employees |
| student |
+----------------+
2 rows in set (0.00 sec)
mysql> select * from employees;
+---------+----------+--------+
| empname | title | salary |
+---------+----------+--------+
| 中签 | 职员 | 5000 |
| 公共 | 职员 | 4500 |
| 寝室 | 职员 | 3500 |
| 就是 | 职员 | 5500 |
| 张三 | 部门经理 | 8000 |
| 李四 | 职员 | 4000 |
| 李帅 | 职员 | 3000 |
| 李波 | 职员 | 3000 |
| 王五 | 职员 | 4000 |
| 高就 | 经理 | 6000 |
+---------+----------+--------+
10 rows in set (0.10 sec)
mysql> create table persons
-> (
-> id int not null,
-> name varchar(20),
-> mgrid varchar(20)
-> );
Query OK, 0 rows affected (0.11 sec)
mysql> insert into persons(id,name) values(1,'zwh1');
Query OK, 1 row affected (0.01 sec)
mysql> insert into persons(id,name) values(2,'zwh2');
Query OK, 1 row affected (0.00 sec)
mysql> alter table persons
-> modify column mgrid
-> int;
Query OK, 2 rows affected (0.07 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> desc persons;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id | int(11) | NO | | NULL | |
| name | varchar(20) | YES | | NULL | |
| mgrid | int(11) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.06 sec)
mysql> select * from persons;
+----+------+-------+
| id | name | mgrid |
+----+------+-------+
| 1 | zwh1 | NULL |
| 2 | zwh2 | NULL |
+----+------+-------+
2 rows in set (0.00 sec)
mysql> insert into persons(id,name,mgrid) values(2,'zwh2','1');
Query OK, 1 row affected (0.00 sec)
mysql> insert into persons(id,name,mgrid) values(4,'zwh4','2');
Query OK, 1 row affected (0.00 sec)
mysql> select * from persons;
+----+------+-------+
| id | name | mgrid |
+----+------+-------+
| 1 | zwh1 | NULL |
| 2 | zwh2 | NULL |
| 2 | zwh2 | 1 |
| 4 | zwh4 | 2 |
+----+------+-------+
4 rows in set (0.00 sec)
mysql> update persons set id=3 where mgrid=1;
Query OK, 1 row affected (0.03 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> update persons set name='zwh3' where mgrid=1;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from persons;
+----+------+-------+
| id | name | mgrid |
+----+------+-------+
| 1 | zwh1 | NULL |
| 2 | zwh2 | NULL |
| 3 | zwh3 | 1 |
| 4 | zwh4 | 2 |
+----+------+-------+
4 rows in set (0.00 sec)
mysql> select id,name,person2.mgrid,person2.name as mgrname
-> from persons inner join persons as person2
-> on persons.id=person2.mgrid;
ERROR 1052 (23000): Column 'id' in field list is ambiguous
mysql> select persons.id,persons.name,person2.mgrid,person2.name as mgrname
-> from persons inner join persons as person2
-> on persons.id=person2.mgrid;
+----+------+-------+---------+
| id | name | mgrid | mgrname |
+----+------+-------+---------+
| 1 | zwh1 | 1 | zwh3 |
| 2 | zwh2 | 2 | zwh4 |
+----+------+-------+---------+
2 rows in set (0.03 sec)
mysql> select persons.id as mgrid,persons.name as mgrname,person2.id,person2.name
-> from persons inner join persons as person2
-> on persons.id=person2.mgrid;
+-------+---------+----+------+
| mgrid | mgrname | id | name |
+-------+---------+----+------+
| 1 | zwh1 | 3 | zwh3 |
| 2 | zwh2 | 4 | zwh4 |
+-------+---------+----+------+
2 rows in set (0.00 sec)
mysql>

mysql'sblobissuitableForStoringBinaryDataWithInareLationalDatabase,而ilenosqloptionslikemongodb,redis和calablesolutionsolutionsolutionsoluntionsoluntionsolundortionsolunsonstructureddata.blobobobissimplobisslowdeperformberbutslowderformandperformancewithlararengedata;

toaddauserinmysql,使用:createUser'username'@'host'Indessify'password'; there'showtodoitsecurely:1)choosethehostcarecarefullytocon trolaccess.2)setResourcelimitswithoptionslikemax_queries_per_hour.3)usestrong,iniquepasswords.4)Enforcessl/tlsconnectionswith

toAvoidCommonMistakeswithStringDatatatPesInMysQl,CloseStringTypenuances,chosethirtightType,andManageEngencodingAndCollationsEttingSefectery.1)usecharforfixed lengengtrings,varchar forvariable-varchar forbariaible length,andtext/blobforlargerdataa.2 seterters seterters seterters

mysqloffersechar,varchar,text,and denumforstringdata.usecharforfixed Lengttrings,varcharerforvariable長度,文本forlarger文本,andenumforenforcingDataAntegrityWithaEtofValues。

優化MySQLBLOB請求可以通過以下策略:1.減少BLOB查詢頻率,使用獨立請求或延遲加載;2.選擇合適的BLOB類型(如TINYBLOB);3.將BLOB數據分離到單獨表中;4.在應用層壓縮BLOB數據;5.對BLOB元數據建立索引。這些方法結合實際應用中的監控、緩存和數據分片,可以有效提升性能。

掌握添加MySQL用戶的方法對於數據庫管理員和開發者至關重要,因為它確保數據庫的安全性和訪問控制。 1)使用CREATEUSER命令創建新用戶,2)通過GRANT命令分配權限,3)使用FLUSHPRIVILEGES確保權限生效,4)定期審計和清理用戶賬戶以維護性能和安全。

chosecharforfixed-lengthdata,varcharforvariable-lengthdata,andtextforlargetextfield.1)chariseffity forconsistent-lengthdatalikecodes.2)varcharsuitsvariable-lengthdatalikenames,ballancingflexibilitibility andperformance.3)

在MySQL中處理字符串數據類型和索引的最佳實踐包括:1)選擇合適的字符串類型,如CHAR用於固定長度,VARCHAR用於可變長度,TEXT用於大文本;2)謹慎索引,避免過度索引,針對常用查詢創建索引;3)使用前綴索引和全文索引優化長字符串搜索;4)定期監控和優化索引,保持索引小巧高效。通過這些方法,可以在讀取和寫入性能之間取得平衡,提升數據庫效率。


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