MySQL Introduction

rpm可讓Linux在安裝軟件包時免除許多複雜的手續。該命令在安裝時常用的參數是 –ivh ,其中i表示將安裝指定的rmp軟件包，V表示安裝時的詳細信息，h表示在安裝期間出現“#”符號來顯示目前的安裝過程。這個符號將持續到安裝完成後才停 止。 

在Ubuntu系統中安裝RPM格式軟件包的方法

Ubuntu的軟件包格式是deb，如果要安裝rpm的包，則要先用alien把rpm轉換成deb。

sudo apt-get install alien #alien默認沒有安裝，所以首先要安裝它

sudo alien xxxx.rpm #將rpm轉換位deb，完成後會生成一個同名的xxxx.deb

sudo dpkg -i xxxx.deb #安裝

不建議

安裝MySQL 

sudo apt-get install mysql-server 

配置MySQL 

注意，在Ubuntu下MySQL缺省是隻允許本地訪問的，如果你要其他機器也能夠訪問的話，那麼需要改變/etc/mysql/my.cnf配置文件了！下面我們一步步地來： 

默認的MySQL安裝之後根用戶是沒有密碼的，所以首先用根用戶進入： 

$mysql -u root 

在這裏之所以用-u root是因爲我現在是一般用戶（firehare），如果不加-u root的話，mysql會以爲是firehare在登錄

進入mysql之後，最要緊的就是要設置Mysql中的root用戶密碼了，否則，Mysql服務無安全可言了。 

mysql> GRANT ALL PRIVILEGES ON *.* TO root@localhost IDENTIFIED BY "123456"; //授予 root用戶 所有數據庫，所有表 全部權限 *.*; //會創建用戶，當然用戶存在的話則不必加"123456" 

即創建用戶時不加 identified選項。否則創建的用戶帶密碼。除非顯示修改

注意，我這兒用的是123456做爲root用戶的密碼，但是該密碼是不安全的，請大家最好使用大小寫字母與數字混合的密碼，且不少於8位。 

這樣的話，就設置好了MySQL中的root用戶密碼了，然後就用root用戶建立你所需要的數據庫。我這裏就以xoops爲例： 

mysql>CREATE DATABASE xoops； 

mysql>GRANT ALL PRIVILEGES ON xoops.* TO xoops_root@localhost IDENTIFIED BY "654321"; 

這樣就建立了一個xoops_roots的用戶，它對數據庫xoops有着全部權限。以後就用xoops_root來對xoops數據庫進行管理，而無需要再用root用戶了，而該用戶的權限也只被限定在xoops數據庫中。 

如果你想進行遠程訪問或控制，那麼你要同時做兩件事： 

其一： 

mysql>GRANT ALL PRIVILEGES ON xoops.* TO xoops_root@"%" IDENTIFIED BY "654321"; 

允許xoops_root用戶可以從任意機器上登入MySQL。 %表示匹配任意 ,但有時這種方法可能失效，那就重新特定一下，不知道哪裏有問題。

其二： 

$sudo gedit /etc/mysql/my.cnf 

新的版本中 

>bind-address=127.0.0.1 => bind-address= 你機器的IP 

這樣就可以允許其他機器訪問MySQL了。bind表示綁定的監聽IP

 On Unix, to install a compressed tar file binary distribution,
   unpack it at the installation location you choose (typically
   /usr/local/mysql). This creates the directories shown in the
   following table.

shell> mysql ;匿名登錄,如果服務器允許的話, 

mysql> SHOW DATABASES;

mysql> USE test

USE, like QUIT, does not require a semicolon. (You can terminate such statements with a semicolon if you like; it does no harm.) The USE statement is special in another way, too: it must be given on a single line.

mysql> QUIT

mysql> SELECT VERSION(), CURRENT_DATE;
+--------------+--------------+
| VERSION()    | CURRENT_DATE |
+--------------+--------------+
| 5.5.0-m2-log | 2009-05-04   |
+--------------+--------------+
1 row in set (0.01 sec)
mysql>

Keywords may be entered in any lettercase. The following queries are equivalent:

mysql> SELECT VERSION(), CURRENT_DATE;
mysql> select version(), current_date;
mysql> SeLeCt vErSiOn(), current_DATE;

Here is another query. It demonstrates that you can use mysql as a simple calculator:

mysql> SELECT SIN(PI()/4), (4+1)*5;
+------------------+---------+
| SIN(PI()/4)      | (4+1)*5 |
+------------------+---------+
| 0.70710678118655 |      25 |
+------------------+---------+
1 row in set (0.02 sec)

mysql> SELECT VERSION(); SELECT NOW();

A command need not be given all on a single line, so lengthy commands that require several lines are not a problem.

Here is a simple multiple-line statement:

mysql> SELECT
    -> USER()
    -> ,
    -> CURRENT_DATE;
+---------------+--------------+
| USER()        | CURRENT_DATE |
+---------------+--------------+
| jon@localhost | 2005-10-11   |
+---------------+--------------+

If you decide you do not want to execute a command that you are in the process of entering, cancel it by typing\c: 取消已輸入但爲被執行的語句。

mysql> SELECT
    -> USER()
    -> \c
mysql>

Here, too, notice the prompt. It switches back to mysql> after you type \c, providing feedback to indicate thatmysql is ready for a new command.

Prompt	Meaning
mysql>	Ready for new command.
->	Waiting for next line of multiple-line command.
'>	Waiting for next line, waiting for completion of a string that began with a single quote (“'”).
">	Waiting for next line, waiting for completion of a string that began with a double quote (“"”).
`>	Waiting for next line, waiting for completion of an identifier that began with a backtick (“`”).
/*>	Waiting for next line, waiting for completion of a comment that began with /*.

 In MySQL, you can write strings surrounded by either “'” or “"” characters 

mysql> SHOW DATABASES;

 SELECT DATABASE().

 SHOW DATABASES does not show databases that you have no privileges for if you do not have the SHOW DATABASES privilege. 

+----------+
| Database |
+----------+
| mysql    | (mysql數據庫存儲了用戶權限)
| test     |
| tmp      |
+----------+

The mysql database describes user access privileges. The test database often is available as a workspace for users to try things out.

mysql> USE test
Database changed

USE, like QUIT, does not require a semicolon. (You can terminate such statements with a semicolon if you like; it does no harm.) The USE statement is special in another way, too: it must be given on a single line.

mysql> CREATE DATABASE menagerie;

shell> mysql -h host -u user -p menagerie
Enter password: ********

mysql> SHOW TABLES;

mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20),
    -> species VARCHAR(20), sex CHAR(1), birth DATE, death DATE);

VARCHAR is a good choice for the name, owner, and species columns because the column values vary in length.