MySQL有很多的可視化管理工具,比如“mysql-workbench”和“sequel-pro-”。 現(xiàn)在我寫MySQL的終端命令操作的文章,是想強化一下自己對于MySQL的理解,總會比使用圖形化的理解透徹,因為我本來就比較喜歡寫代碼。同時寫出來這些文章,是想要給大家當個參考,希望也能對大家有所幫助,有所提升,這就是我為什么要寫終端操作MySQL的文章了。
注意:MySQL數(shù)據(jù)庫命令不區(qū)分大小寫。但在MAC的終端,如果你想使用tab自動補全命令,那么你就必須使用大寫,這樣MAC的終端才會幫你補全命令,否則你按N遍tab都不會有響應(yīng)。
1、數(shù)據(jù)庫(database)管理
1.1 create 創(chuàng)建數(shù)據(jù)庫
create database firstDB;
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | firstDB | | mysql | | performance_schema | +--------------------+ 4 rows in set (0.00 sec)
alter 命令修改數(shù)據(jù)庫編碼:
默認創(chuàng)建的數(shù)據(jù)庫默認不支持中文字符,如果我們需要它支持中文字符,則將它的編碼設(shè)置為utf8格式:
mysql> ALTER DATABASE testDB CHARACTER SET UTF8; Query OK, 1 row affected (0.00 sec)
mysql> use firstDB; Database changed
mysql> select database(); +------------+ | database() | +------------+ | firstdb | +------------+ 1 row in set (0.00 sec)
mysql> drop database firstDB; Query OK, 0 rows affected (0.00 sec)
2、數(shù)據(jù)表(table)管理
我們首先創(chuàng)建一個數(shù)據(jù)庫,提供我們往后的使用:
mysql> create database testDB; Query OK, 1 row affected (0.00 sec)
創(chuàng)建后記得用use命令進入(使用)數(shù)據(jù)庫,不然后面的操作都會不成功的。
mysql> create table PEOPLE (
-> ID int AUTO_INCREMENT PRIMARY KEY,
-> NAME varchar(20) not null,
-> AGE int not null,
-> BIRTHDAY datetime);
Query OK, 0 rows affected (0.01 sec)
顯示當前數(shù)據(jù)庫所有的數(shù)據(jù)表
mysql> show tables; +------------------+ | Tables_in_testdb | +------------------+ | PEOPLE | +------------------+ 1 row in set (0.00 sec)
mysql> desc PEOPLE
-> ;
+----------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+----------------+
| ID | int(11) | NO | PRI | NULL | auto_increment |
| NAME | varchar(20) | NO | | NULL | |
| AGE | int(11) | NO | | NULL | |
| BIRTHDAY | datetime | YES | | NULL | |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)
2.4 alter 修改表結(jié)構(gòu)(增、刪、改)
默認創(chuàng)建的表不支持中文字符,所以需將表編碼設(shè)置為utf8:
mysql> ALTER TABLE KEYCHAIN CONVERT TO CHARACTER SET UTF8; Query OK, 1 row affected (0.02 sec) Records: 1 Duplicates: 0 Warnings: 0
mysql> alter table PEOPLE add star BOOL; Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0
提示:在MySQL里,布爾類型會自動轉(zhuǎn)換為tinyint(1)類型。
我們不妨使用desc去查看一下PEOPLE表結(jié)構(gòu):
mysql> desc PEOPLE; +----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+----------------+ | ID | int(11) | NO | PRI | NULL | auto_increment | | NAME | varchar(20) | NO | | NULL | | | AGE | int(11) | NO | | NULL | | | BIRTHDAY | datetime | YES | | NULL | | | star | tinyint(1) | YES | | NULL | | +----------+-------------+------+-----+---------+----------------+ 5 rows in set (0.00 sec)
現(xiàn)在,你該相信我了吧?
mysql> alter table PEOPLE MODIFY star int; Query OK, 0 rows affected (0.01 sec) Records: 0 Duplicates: 0 Warnings: 0
我們再次使用desc查看PEOPLE表結(jié)構(gòu):
mysql> desc PEOPLE; +----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+----------------+ | ID | int(11) | NO | PRI | NULL | auto_increment | | NAME | varchar(20) | NO | | NULL | | | AGE | int(11) | NO | | NULL | | | BIRTHDAY | datetime | YES | | NULL | | | star | int(11) | YES | | NULL | | +----------+-------------+------+-----+---------+----------------+ 5 rows in set (0.00 sec)
mysql> alter table PEOPLE DROP column star; Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0
刪除后,再次查看PEOPLE表結(jié)構(gòu):
mysql> desc PEOPLE; +----------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+----------------+ | ID | int(11) | NO | PRI | NULL | auto_increment | | NAME | varchar(20) | NO | | NULL | | | AGE | int(11) | NO | | NULL | | | BIRTHDAY | datetime | YES | | NULL | | +----------+-------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec)
刪除字段成功,現(xiàn)在我們已經(jīng)不能看到star的字段了。
mysql> RENAME TABLE PEOPLE TO NEW_PEOPLE; Query OK, 0 rows affected (0.00 sec)
2.5 create 利用已有數(shù)據(jù)創(chuàng)建新表
mysql> create table newTable select * from PEOPLE; Query OK, 0 rows affected (0.01 sec) Records: 0 Duplicates: 0 Warnings: 0
我們查看一下目前數(shù)據(jù)庫存在的表:
mysql> show tables; +------------------+ | Tables_in_testdb | +------------------+ | PEOPLE | | newTable | +------------------+ 2 rows in set (0.00 sec)
3、數(shù)據(jù)的操作及管理
數(shù)據(jù)表的基本操作,包含增、刪、改、查數(shù)據(jù)。
以下命令均在PEOPLE表上操作。
PEOPLE表目前是沒有數(shù)據(jù)的,它是空的數(shù)據(jù)表,我們現(xiàn)在先添加一些數(shù)據(jù)。
insert into 命令添加數(shù)據(jù):
mysql> insert into PEOPLE VALUES (null, 'Anny', 22, '1992-05-22'); Query OK, 1 row affected (0.00 sec)
使用select命令查看表(會在后面介紹),現(xiàn)在我們查看PEOPLE數(shù)據(jù)表的數(shù)據(jù):
mysql> select * from PEOPLE; +----+------+-----+---------------------+ | ID | NAME | AGE | BIRTHDAY | +----+------+-----+---------------------+ | 1 | Anny | 22 | 1992-05-22 00:00:00 | +----+------+-----+---------------------+ 1 row in set (0.00 sec)
數(shù)據(jù)表現(xiàn)在有一條數(shù)據(jù)。
我們多添加幾條數(shù)據(jù),如:
mysql> select * from PEOPLE; +----+--------+-----+---------------------+ | ID | NAME | AGE | BIRTHDAY | +----+--------+-----+---------------------+ | 1 | Anny | 22 | 1992-05-22 00:00:00 | | 2 | Garvey | 23 | 1991-05-22 00:00:00 | | 3 | Lisa | 25 | 1989-05-22 00:00:00 | | 4 | Nick | 24 | 1990-05-22 00:00:00 | | 5 | Rick | 24 | 1991-05-22 00:00:00 | +----+--------+-----+---------------------+ 5 rows in set (0.00 sec)
delete 命令刪除數(shù)據(jù):
mysql> delete from PEOPLE where name = 'Lisa'; Query OK, 1 row affected (0.01 sec)
再次查詢PEOPLE表:
mysql> select * from PEOPLE; +----+--------+-----+---------------------+ | ID | NAME | AGE | BIRTHDAY | +----+--------+-----+---------------------+ | 1 | Anny | 22 | 1992-05-22 00:00:00 | | 2 | Garvey | 23 | 1991-05-22 00:00:00 | | 4 | Nick | 24 | 1990-05-22 00:00:00 | | 5 | Rick | 24 | 1991-05-22 00:00:00 | +----+--------+-----+---------------------+ 4 rows in set (0.00 sec)
已經(jīng)看不到名為“Lisa”的數(shù)據(jù)了。
update 命令修改數(shù)據(jù):
mysql> update PEOPLE set name='Calvin' where name = 'Garvey'; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0
查詢PEOPLE表內(nèi)容:
mysql> select * from PEOPLE; +----+--------+-----+---------------------+ | ID | NAME | AGE | BIRTHDAY | +----+--------+-----+---------------------+ | 1 | Anny | 22 | 1992-05-22 00:00:00 | | 2 | Calvin | 23 | 1991-05-22 00:00:00 | | 4 | Nick | 24 | 1990-05-22 00:00:00 | | 5 | Rick | 24 | 1991-05-22 00:00:00 | +----+--------+-----+---------------------+ 4 rows in set (0.00 sec)
名為“Garvey”的記錄已經(jīng)修改為“Calvin”。
select 命令查詢數(shù)據(jù),最簡單的就是查詢表的所有數(shù)據(jù),也就是我們最初使用到的那條命令:
mysql> select * from PEOPLE; +----+--------+-----+---------------------+ | ID | NAME | AGE | BIRTHDAY | +----+--------+-----+---------------------+ | 1 | Anny | 22 | 1992-05-22 00:00:00 | | 2 | Calvin | 23 | 1991-05-22 00:00:00 | | 4 | Nick | 24 | 1990-05-22 00:00:00 | | 5 | Rick | 24 | 1991-05-22 00:00:00 | +----+--------+-----+---------------------+ 4 rows in set (0.00 sec)
格式:select * from <表名>,*代表所有字段。
查詢數(shù)據(jù)時也可指定顯示的(列)字段:
mysql> select NAME, AGE, BIRTHDAY from PEOPLE; +--------+-----+---------------------+ | NAME | AGE | BIRTHDAY | +--------+-----+---------------------+ | Anny | 22 | 1992-05-22 00:00:00 | | Calvin | 23 | 1991-05-22 00:00:00 | | Nick | 24 | 1990-05-22 00:00:00 | | Rick | 24 | 1991-05-22 00:00:00 | +--------+-----+---------------------+ 4 rows in set (0.00 sec)
格式:select <字段名,字段名,…> from <表名>。
select查詢命令還有很多的高級用法,比如用來查找不重復(fù)(distinct)的數(shù)據(jù),使數(shù)據(jù)按條件排序(order by),按查詢條件顯示數(shù)據(jù)(where)等等。這些都會在下一篇文章作重點介紹,請大家繼續(xù)留意我的博客,謝謝。
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