MySQL基本操做

肯定MySQL服務端是否開啓的方法：[牢記:服務端關閉,是無法進入MySQL數據庫的]
-點擊'個人電腦'(右鍵)->'管理'->'服務應用程序'->'服務'(雙擊)->查看MySQL狀態
-在控制檯CMD中輸入:net start mysql57(回車)->'服務啓動成功'
net stop mysql57(回車)->'服務成功中止'

打開MySQL數據庫的方法：
-進入控制檯CMD;輸入mysql -u root -p(回車);輸入密碼(回車)[進入數據庫]
-前提是把[C:\Program Files\MySQL\bin]寫入環境變量中
-打開MySQL客戶端:MySQL5.7Command Line Client-Unicode;輸入密碼(回車)[進入數據庫]
-打開MySQL Workbench 6.3 CE[鏈接進入數據庫]

\s:查看MySQL相關配置信息
-Current user:root@localhost
-Using delimiter:;[命令分隔符]
-Server version:5.7.20-log[==SELECT VERSION();]
-Client characterset:gbk
-Conn. characterset:gbk
-TCP port:3306
注意的問題:
-CMD進入MySQL數據庫客戶端和鏈接端字符編碼爲UTF8(若是爲GBK須要修改成UTF8)
-方法:在配置文件my.ini中寫入default-character-set=utf8/character-set-server=utf8
-MySQL客戶端進入MySQL數據庫則客戶端和鏈接端字符編碼爲UTF8(無需修改)

\c:刪除敲入的字符
退出MySQL數據庫的方法:
-exit;
-quit;

\T 文本絕對路徑\file.txt:開啓MySQL日誌
\t:關閉日誌

注意:
在CMD輸入用戶帳號:mysql -u qinlan -p ->輸入密碼:*****[可進入MySQL:數據庫管理員DBadmin]


--建立數據庫
CREATE DATABASE IF NOT EXISTS db_train;
USE db_train;
--建立數據表tb_train_user
CREATE TABLE IF NOT EXISTS tb_train_user(
userid TINYINT KEY AUTO_INCREMENT,
username VARCHAR(10) NOT NULL,
sex ENUM('男','女','保密') DEFAULT '保密',
age INT UNSIGNED DEFAULT 20,
birth YEAR,
proid TINYINT UNSIGNED,
score FLOAT NOT NULL
)AUTO_INCREMENT=100 ENGINE=INNODB CHARSET=UTF8;
SHOW TABLES;
--查看錶結構
DESC tb_train_user;
--查看數據表建立信息
SHOW CREATE TABLE tb_train_user;
--插入數據
INSERT tb_train_user(username,sex,age,birth,proid,score) VALUES
('曹操','男',45,'1992',2,98.4),
('呂布',DEFAULT,36,'2012',1,70.1),
('甄姬','女',28,'2018',5,82.8),
('趙子龍','男',DEFAULT,'2020',4,96.5),
('關鳳','女',22,'2016',3,83.7),
('黃月英','女',30,'2011',1,89.6),
('James','保密',35,'2014',5,75.3),
('Nike','男',28,'2018',4,87.8);
SLECT * FROM tb_train_user;

--建立數據表tb_train_province
CREATE TABLE IF NOT EXISTS tb_train_province(
id TINYINT UNSIGNED KEY AUTO_INCREMENT,
proname VARCHAR(5) NOT NULL UNIQUE
);
--插入數據
INSERT tb_train_province(proname) VALUES
('北京'),
('深圳'),
('上海'),
('成都'),
('蘇州'),
('西安');

------建立數據表tb_train_cpp1:修改表結構
CREATE TABLE IF NOT EXISTS tb_train_cpp1(
id TINYINT UNSIGNED,
name VARCHAR(10),
age INT UNSIGNED
);
--添加字段:
ALTER TABLE tb_train_cpp1 ADD sex ENUM('男','女') DEFAULT '男';
ALTER TABLE tb_train_cpp1 ADD card CHAR(3) NOT NULL UNIQUE AFTER name;

ALTER TABLE tb_train_cpp1
ADD sex ENUM('男','女') DEFAULT '男',
ADD card CHAR(3) NOT NULL UNIQUE AFTER name;[等價於以上2條命令]
--刪除字段:
ALTER TABLE tb_train_cpp1 DROP sex;
ALTER TABLE tb_train_cpp1 DROP card;

ALTER TABLE tb_train_cpp1
DROP sex,
DROP card;[等價於以上2條命令]
--修改字段(屬性):
ALTER TABLE tb_train_cpp1 MODIFY name VARCHAR(15) NOT NULL;
--修改表名:
ALTER TABLE tb_train_cpp1 RENAME tb_train_cpp;
ALTER TABLE tb_train_cpp RENAME tb_train_cpp1;

--設置默認值:
ALTER TABLE tb_train_cpp1 ALTER age SET DEFAULT 18;
ALTER TABLE tb_train_cpp1 ALTER age DROP DEFAULT;[刪除默認值]
--設置主鍵:
ALTER TABLE tb_train_cpp1 ADD PRIMARY KEY(id);
ALTER TABLE tb_train_cpp1 DROP PRIMARY KEY;[刪除主鍵]
--設置惟一:主鍵只能有一個+惟一能夠有多個
ALTER TABLE tb_train_cpp1 ADD PRIMARY KEY(id);
ALTER TABLE tb_train_cpp1 ADD UNIQUE(name);
ALTER TABLE tb_train_cpp1 DROP INDEX name;[刪除惟一]
--插入數據/刪除數據:
INSERT tb_train_cpp1(id,name,age) VALUES
(1,'M1',12),
(3,'M2',6),
(8,'M3',25),
(12,'M4',20);
DELETE FROM tb_train_cpp1 WHERE id=8;[刪除1條記錄]
TRUNCATE TABLE tb_train_cpp1;[刪除全部記錄]