Common function script
1. Export the entire database
mysqldump -u 用户名 -p –default-character-set=latin1 数据库名 > 导出的文件名(数据库默认编码是latin1)
mysqldump -u wcnc -p smgp_apps_wcnc > wcnc.sql
2. Export a table
mysqldump -u 用户名 -p 数据库名 表名> 导出的文件名
mysqldump -u wcnc -p smgp_apps_wcnc users> wcnc_users.sql
3. Export a database structure
mysqldump -u wcnc -p -d –add-drop-table smgp_apps_wcnc >d:wcnc_db.sql
-d 没有数据 –add-drop-table 在每个create语句之前增加一个drop table
4. Import database
A:常用source 命令
进入mysql数据库控制台,
如mysql -u root -p
mysql>use 数据库
然后使用source命令,后面参数为脚本文件(如这里用到的.sql)
mysql>source wcnc_db.sql
B:使用mysqldump命令
mysqldump -u username -p dbname < filename.sql
C:使用mysql命令
mysql -u username -p -D dbname < filename.sql
start and exit
1. Enter MySQL: Start MySQL Command Line Client (DOS interface of MySQL), and directly enter the password during installation. The prompt at this time is: mysql>
2. Exit MySQL: quit or exit
library operation
1. Create a database
Command: create database <database name>
For example: create a database named sqlroad
mysql> create database sqlroad;
2. Display all databases
Command: show databases (note: there is an s at the end)
mysql> show databases;
3. Delete the database
Command: drop database <database name>
For example: delete the database named sqlroad
mysql> drop database sqlroad;
4. Connect to the database
Command: use <database name>
For example: if the sqlroad database exists, try to access it:
mysql> use sqlroad;
Screen prompt: Database changed
5. View the currently used database
mysql> select database();
6. Table information contained in the current database:
mysql> show tables; (note: there is an s at the end)
Table operation, a database should be connected before the operation
1. Create a table
命令:create table <表名> ( <字段名> <类型> [,..<字段名n> <类型n>]);
mysql> create table MyClass(
> id int(4) not null primary key auto_increment,
> name char(20) not null,
> sex int(4) not null default ’′,
> degree double(16,2));
2. Obtain the table structure
命令:desc 表名,或者show columns from 表名
mysql>DESCRIBE MyClass
mysql> desc MyClass;
mysql> show columns from MyClass;
3. Delete table
命令:drop table <表名>
例如:删除表名为 MyClass 的表
mysql> drop table MyClass;
4. Insert data
命令:insert into <表名> [( <字段名>[,..<字段名n> ])] values ( 值 )[, ( 值n )]
例如,往表 MyClass中插入二条记录, 这二条记录表示:编号为的名为Tom的成绩为.45, 编号为 的名为Joan 的成绩为.99,编号为 的名为Wang 的成绩为.5.
mysql> insert into MyClass values(1,’Tom’,96.45),(2,’Joan’,82.99), (2,’Wang’, 96.59);
5. Query the data in the table
1)、查询所有行
命令:select <字段,字段,...> from < 表名 > where < 表达式 >
例如:查看表 MyClass 中所有数据
mysql> select * from MyClass;
2)、查询前几行数据
例如:查看表 MyClass 中前行数据
mysql> select * from MyClass order by id limit 0,2;
或者:
mysql> select * from MyClass limit 0,2;
6. Delete the data in the table
命令:delete from 表名 where 表达式
例如:删除表 MyClass中编号为 的记录
mysql> delete from MyClass where id=1;
7. Modify the data in the table: update table name set field = new value,...where condition
mysql> update MyClass set name=’Mary’where id=1;
8. Add fields to the table:
命令:alter table 表名 add字段 类型 其他;
例如:在表MyClass中添加了一个字段passtest,类型为int(4),默认值为
mysql> alter table MyClass add passtest int(4) default ’′
9. Change the table name:
命令:rename table 原表名 to 新表名;
例如:在表MyClass名字更改为YouClass
mysql> rename table MyClass to YouClass;
更新字段内容
update 表名 set 字段名 = 新内容
update 表名 set 字段名 = replace(字段名,’旧内容’, 新内容’)
update article set content=concat(‘ ’,content);
Field types and database operations
1. INT[(M)] type: normal-sized integer type
2. DOUBLE[(M,D)] [ZEROFILL] type: normal size (double precision) floating point number type
3. DATE date type: the supported range is -01-01 to -12-31. MySQL displays DATE values in YYYY-MM-DD format, but allows you to assign values to DATE columns using strings or numbers
4. CHAR(M) type: fixed-length string type, when stored, always fill the right side with spaces to the specified length
5. BLOB TEXT type, the maximum length is (2^16-1) characters.
6. VARCHAR type: variable length string type
7. Import database table
创建.sql文件
先产生一个库如auction.c:mysqlbin>mysqladmin -u root -p creat auction,会提示输入密码,然后成功创建。
导入auction.sql文件
c:mysqlbin>mysql -u root -p auction < auction.sql。
通过以上操作,就可以创建了一个数据库auction以及其中的一个表auction。
8. modify database
在mysql的表中增加字段:
alter table dbname add column userid int(11) not null primary key auto_increment;
这样,就在表dbname中添加了一个字段userid,类型为int(11)。
9. Authorization of mysql database
mysql>grant select,insert,delete,create,drop
on *.* (或test.*/user.*/..)
to 用户名@localhost
identified by ‘密码’;
如:新建一个用户帐号以便可以访问数据库,需要进行如下操作:
mysql> grant usage
-> ON test.*
-> TO testuser@localhost;
Query OK, 0 rows affected (0.15 sec)
此后就创建了一个新用户叫:testuser,这个用户只能从localhost连接到数据库并可以连接到test 数据库。下一步,我们必须指定testuser这个用户可以执行哪些操作:
mysql> GRANT select, insert, delete,update
-> ON test.*
-> TO testuser@localhost;
Query OK, 0 rows affected (0.00 sec)
此操作使testuser能够在每一个test数据库中的表执行SELECT,INSERT和DELETE以及UPDATE查询操作。现在我们结束操作并退出MySQL客户程序:
mysql> exit
DDL operation
1: Use the SHOW statement to find out what databases currently exist on the server:
mysql> SHOW DATABASES;
2. Create a database MYSQLDATA
mysql> Create DATABASE MYSQLDATA;
3: Select the database you created
mysql> USE MYSQLDATA; (Press the Enter key when Database changed appears, indicating that the operation is successful!)
4: Check what tables exist in the current database
mysql> SHOW TABLES;
5: Create a database table
mysql> Create TABLE MYTABLE (name VARCHAR(20), sex CHAR(1));
6: Display the structure of the table:
mysql> DESCRIBE MYTABLE;
7: Add records to the table
mysql> insert into MYTABLE values (“hyq”,”M”);
8: Load the data into the database table in text mode (eg D:/mysql.txt)
mysql> LOAD DATA LOCAL INFILE “D:/mysql.txt”INTO TABLE MYTABLE;
9: Import the .sql file command (eg D:/mysql.sql)
mysql>use database;
mysql>source d:/mysql.sql;
10: Delete table
mysql>drop TABLE MYTABLE;
11: Empty table
mysql>delete from MYTABLE;
12: Update the data in the table
mysql>update MYTABLE set sex=”f”where name=’hyq’;