MySQL基础知识学习之创建MySQL数据库和表
虚构一个微型在线书店的数据库和数据，作为后续MySQL脚本的执行源，方便后续MySQL和SQL的练习。
在虚构这个库的过程中，主要涉及的是如何使用命令行管理 MySQL数据库对象：数据库、表、索引、外键等；另一个更为重要的是如何Mock对应表的数据。
虚构书店数据库的dump脚本：Github
数据库（Database）
将要创建的虚拟书店的数据库名为： mysql_practice;
创建数据库的语法：
CREATE DATABASE [IF NOT EXISTS] database_name[CHARACTER SET charset_name][COLLATE collation_name]
IF NOT EXISTS： 可选项，避免数据库已经存在时报错。
CHARACTER SET：可选项，不指定的时候会默认给个。
查看当前MySQL Server支持的字符集(character set):
show character set; -- 方法1show charset; -- 方法2show char set; -- 方法3
COLLATE：针对特定
character set比较字符串的规则集合；可选项，不指定的时候会默认给个。获取
charater set的collationsshow collation like 'utf8%';
collation名字的规则：
charater_set_name_ci或者charater_set_name_cs或charater_set_name_bin；_ci表示不区分大小写，_cs表示区分大小写；_bin表示用编码值比较。示例：
CREATE DATABASE my_test_tb CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci;
TODO： 关于 character set和collations，内容稍微有点多，后面会单独记一篇文章。
登录的时候选择数据库
mysql -uroot -D database_name -p
登录后选择数据库
use database_name;
查看当前选的数据库
select database();
创建新数据库
create database if not exists mysql_practice;
通过下面的语句可以检查创建的数据库：
show create database mysql_practice;
可以看到，如果创建数据库时候没有指定 character set 和 collate 的话，会默认指定一套。
显示所有当前账户可见的数据库
show databases;
删除数据库
drop database if exists mysql_practice;
MySQL中 schema 是 database 的同义词，因此也可以使用下面语句删除数据库：
drop schema if exists mysql_practice;
数据表（Table）
MySQL创建数据表的语法
CREATE TABLE [IF NOT EXISTS] table_name( column_1_definition, column_2_definition, ..., table_constraints) ENGINE=storage_engine;
表列的定义语法：
column_name data_type(length) [NOT NULL] [DEFAULT value] [AUTO_INCREMENT] column_constraint;
表的约束（Table Constraints）: UNIQUE, CHECK, PRIMARY KEY and FOREIGN KEY.
查看表的定义
desc table_name;
创建mysql_practice数据表
USE mysql_practice;DROP TABLE IF EXISTS customer_order;DROP TABLE IF EXISTS book;DROP TABLE IF EXISTS book_category;DROP TABLE IF EXISTS customer_address;DROP TABLE IF EXISTS customer;DROP TABLE IF EXISTS region;-- region，数据使用: https://github.com/xiangyuecn/AreaCity-JsSpider-StatsGovCREATE TABLE IF NOT EXISTS region(id INT AUTO_INCREMENT, pid INT NOT NULL, deep INT NOT NULL, name VARCHAR(200) NOT NULL, pinyin_prefix VARCHAR(10) NOT NULL, pinyin VARCHAR(200) NOT NULL, ext_id VARCHAR(100) NOT NULL, ext_name VARCHAR(200) NOT NULL, PRIMARY KEY(id));-- customerCREATE TABLE IF NOT EXISTS customer( id INT AUTO_INCREMENT, no VARCHAR(50) NOT NULL, first_name VARCHAR(255) NOT NULL,last_name VARCHAR(255) NOT NULL, status VARCHAR(20) NOT NULL, phone_number VARCHAR(20) NULL, updated_at DATETIME NOT NULL, created_at DATETIME NOT NULL, PRIMARY KEY(id), unique(no)) ENGINE=INNODB;-- customer addressCREATE TABLE IF NOT EXISTS customer_address(id INT AUTO_INCREMENT, customer_id INT NOT NULL, area_id INT NULL, address_detail VARCHAR(200) NULL,is_default bit NOT NULL,updated_at DATETIME NOT NULL, created_at DATETIME NOT NULL, PRIMARY KEY(id), FOREIGN KEY(customer_id) REFERENCES customer (id) ON UPDATE RESTRICT ON DELETE CASCADE) ENGINE=INNODB;-- book categoryCREATE TABLE IF NOT EXISTS book_category(id INT AUTO_INCREMENT, code VARCHAR(200) NOT NULL,name VARCHAR(200) NOT NULL, parent_id INT NULL, deep INT NULL,updated_at DATETIME NOT NULL, created_at DATETIME NOT NULL, PRIMARY KEY(id));-- bookCREATE TABLE IF NOT EXISTS book(id INT AUTO_INCREMENT, category_id INT NOT NULL, no VARCHAR(50) NOT NULL, name VARCHAR(200) NOT NULL, status VARCHAR(50) NOT NULL, unit_price DOUBLE NOT NULL, author VARCHAR(50) NULL, publish_date DATETIME NULL, publisher VARCHAR(200) NOT NULL,updated_at DATETIME NOT NULL, created_at DATETIME NOT NULL, PRIMARY KEY(id), FOREIGN KEY (category_id) REFERENCES book_category (id) ON UPDATE RESTRICT ON DELETE CASCADE);-- ordersCREATE TABLE IF NOT EXISTS customer_order(id INT AUTO_INCREMENT, no VARCHAR(50) NOT NULL, customer_id INT NOT NULL, book_id INT NOT NULL, quantity INT NOT NULL, total_price DOUBLE NOT NULL, discount DOUBLE NULL, order_date DATETIME NOT NULL,updated_at DATETIME NOT NULL, created_at DATETIME NOT NULL, PRIMARY KEY(id), FOREIGN KEY (customer_id) REFERENCES customer(id) ON UPDATE RESTRICT ON DELETE CASCADE, FOREIGN KEY (book_id) references book (id) on update restrict on delete cascade) ENGINE=INNODB;
导入region数据
下载region csv数据：【三级】省市区 数据下载.
导入语句：
LOAD DATA INFILE '/tmp/ok_data_level3.csv' INTO TABLE region FIELDS TERMINATED BY ',' ENCLOSED BY '"'LINES TERMINATED BY '\n'IGNORE 1 ROWS;
导入如果报错：
ERROR 1290 (HY000): The MySQL server is running with the --secure-file-priv option so it cannot execute this statement
通过命令
mdfind -name my.cnf找到mysql配置文件my.cnf；解决办法 (还没实际测试过，大都使用的是
LOATA DATA LOCAL INFILE方式)
或者使用 LOAD DATA LOCAL INFILE代替 LOAD DATA INFILE 即：
LOAD DATA LOCAL INFILE '/tmp/ok_data_level3.csv' INTO TABLE region FIELDS TERMINATED BY ',' ENCLOSED BY '"'LINES TERMINATED BY '\n'IGNORE 1 ROWS;
如果报错：
Error Code: 3948. Loading local data is disabled; this must be enabled on both the client and server sides
或者报错:
ERROR 1148 (42000): The used command is not allowed with this MySQL version
查看配置:
show variables like "local_infile";修改配置:
set global local_infile = 1;
生成Customer数据
创建一个SP：
USE mysql_practice;DROP PROCEDURE IF EXISTS sp_generate_customers;DELIMITER $$CREATE PROCEDURE sp_generate_customers()BEGIN-- Generate 10000 customer and customer_addressset @fNameIndex = 1;set @lNameIndex = 1;loop_label_f: LOOPIF @fNameIndex > 100 THENLEAVE loop_label_f;END IF; set @fName = ELT(@fNameIndex, "James","Mary","John","Patricia","Robert","Linda","Michael","Barbara","William","Elizabeth","David","Jennifer","Richard","Maria","Charles","Susan","Joseph","Margaret","Thomas","Dorothy","Christopher","Lisa","Daniel","Nancy","Paul","Karen","Mark","Betty","Donald","Helen","George","Sandra","Kenneth","Donna","Steven","Carol","Edward","Ruth","Brian","Sharon","Ronald","Michelle","Anthony","Laura","Kevin","Sarah","Jason","Kimberly","Matthew","Deborah","Gary","Jessica","Timothy","Shirley","Jose","Cynthia","Larry","Angela","Jeffrey","Melissa","Frank","Brenda","Scott","Amy","Eric","Anna","Stephen","Rebecca","Andrew","Virginia","Raymond","Kathleen","Gregory","Pamela","Joshua","Martha","Jerry","Debra","Dennis","Amanda","Walter","Stephanie","Patrick","Carolyn","Peter","Christine","Harold","Marie","Douglas","Janet","Henry","Catherine","Carl","Frances","Arthur","Ann","Ryan","Joyce","Roger","Diane"); loop_label_last: LOOPIF @lNameIndex > 100 THENLEAVE loop_label_last;END IF;SET @lName = ELT(@lNameIndex, "Smith","Johnson","Williams","Jones","Brown","Davis","Miller","Wilson","Moore","Taylor","Anderson","Thomas","Jackson","White","Harris","Martin","Thompson","Garcia","Martinez","Robinson","Clark","Rodriguez","Lewis","Lee","Walker","Hall","Allen","Young","Hernandez","King","Wright","Lopez","Hill","Scott","Green","Adams","Baker","Gonzalez","Nelson","Carter","Mitchell","Perez","Roberts","Turner","Phillips","Campbell","Parker","Evans","Edwards","Collins","Stewart","Sanchez","Morris","Rogers","Reed","Cook","Morgan","Bell","Murphy","Bailey","Rivera","Cooper","Richardson","Cox","Howard","Ward","Torres","Peterson","Gray","Ramirez","James","Watson","Brooks","Kelly","Sanders","Price","Bennett","Wood","Barnes","Ross","Henderson","Coleman","Jenkins","Perry","Powell","Long","Patterson","Hughes","Flores","Washington","Butler","Simmons","Foster","Gonzales","Bryant","Alexander","Russell","Griffin","Diaz","Hayes");-- insert into customerINSERT INTO customer(no, first_name, last_name, status, phone_number, updated_at, created_at) values(REPLACE(LEFT(uuid(), 16), '-', ''),@fName, @lName, 'ACTIVE',null, curdate(), curdate() ); -- insert into customer_address set @randomArea = 0; SELECT id into @randomArea FROM region where deep = 2 ORDER BY RAND() LIMIT 1; INSERT INTO customer_address(customer_id, area_id, address_detail, is_default, updated_at, created_at) VALUES(@@Identity, @randomArea, '', 1, curdate(), curdate() );set @lNameIndex = @lNameIndex + 1;END LOOP loop_label_last; SET @lNameIndex = 1; -- Note: assign 1 to last name index, for next loop.SET @fnameIndex = @fnameIndex + 1; END LOOP loop_label_f;-- update address_detail in customer_addressUPDATE customer_address caJOIN region r on ca.area_id = r.id and r.deep = 2join region r2 on r.pid = r2.id and r2.deep = 1join region r3 on r2.pid = r3.id and r3.deep = 0SET ca.address_detail = concat(r3.ext_name, r2.ext_name, r.ext_name);END $$DELIMITER ;
调用SP:
call sp_generate_customers();
生成产品分类和产品数据
第零步： 手动插入产品分类到product_category表中
INSERT INTO product_category(code,name, parent_id, deep, updated_at, created_at)VALUES('BOOK', 'Book', 0, 0, curdate(), curdate()),('BOOK_CODE', 'Code Book', 1, 1, curdate(), curdate()),('BOOK_CHIDREN', 'Children Book', 1, 1, curdate(), curdate()),('BOOK_SCIENCE', 'Science Book', 1, 1, curdate(), curdate());
第一步： 用Python写个爬虫工具，抓取书店的商品信息。
下面是抓取当当搜索“科学”关键字的书籍列表。
import requestsimport csvfrom bs4 import BeautifulSoupdef crawl(url): res = requests.get(url) res.encoding = 'gb18030' soup = BeautifulSoup(res.text, 'html.parser') n = 0 section = soup.find('ul', id='component_59') allLIs = section.find_all('li') #print(allLIs) with open('output_science.csv', 'w', encoding='utf8') as f: csv_writer = csv.writer(f, delimiter='#') # 由于内容里有','，因此这里指定'#'作为csv分隔符 csv_writer.writerow(['序号', '书名', '价格', '作者', '出版时间', '出版社']) for books in allLIs: title = books.select('.name')[0].text.strip().split(' ', 1)[0].strip() price = books.select('.search_pre_price')[0].text.strip('¥') authorInfo = books.select('.search_book_author')[0].text.strip().split('/') author = authorInfo[0] publishDate = authorInfo[1] publisher = authorInfo[2] n += 1 csv_writer.writerow([n, title, price, author, publishDate, publisher])url = 'http://search.dangdang.com/?key=%BF%C6%D1%A7&act=input'crawl(url)
第二步： 导入csv数据到MySQL数据表mock_science中。
CREATE TABLE `mock_science` ( `id` int(11) NOT NULL, `name` varchar(200) DEFAULT NULL, `price` double DEFAULT NULL, `author` varchar(100) DEFAULT NULL, `publish_date` varchar(100) DEFAULT NULL, `publisher` varchar(100) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
第三步： 插入科学类书信息到product表中
INSERT book(category_id, no, name, status,unit_price, author,publish_date,publisher, updated_at, created_at)SELECT 4,REPLACE(LEFT(uuid(), 16), '-', ''),name,'ACTIVE',price,author,publish_date,publisher,curdate(),curdate()FROM mock_science;
循环第一到第三步，可以插入更多的产品信息。练习数据库最终抓取了JAVA，儿童，科学三个关键搜索出的第一页书籍。
生成订单数据
随机生成订单数据的SP(注意：这个sp生成的数据，还需要进一步处理):
USE mysql_practice;DROP PROCEDURE IF EXISTS sp_generate_orders;DELIMITER $$-- Reference: https://www.mysqltutorial.org/select-random-records-database-table.aspx-- Generate orders for last two years.-- each day have orders range: [500, 5000]CREATE PROCEDURE sp_generate_orders()BEGINSET @startDate = '2020-03-01';SET @endDate = curdate();loop_label_p: LOOPIF @startDate > @endDate THENLEAVE loop_label_p; END IF;SET @randCustomerTotal = FLOOR(RAND()*50) + 100; SET @randBookTotal = FLOOR(RAND()*5) + 1; SET @randQty = FLOOR(RAND()*3) + 1; SET @query1 = CONCAT('INSERT INTO customer_order(no, customer_id, book_id, quantity, total_price,discount, order_date, updated_at, created_at)'); SET @query1 = CONCAT(@query1, ' select ', "'", uuid(), "'",', c.id, p.id,', @randQty, ', 0, 0, ', "'",@startDate,"'", ',', "'",curdate(),"'" ,',', "'",curdate(),"'"); SET @query1 = CONCAT(@query1, ' FROM (select id from customer ORDER BY RAND() LIMIT ', @randCustomerTotal,') c join '); SET @query1 = CONCAT(@query1, ' (select id from book order by rand() limit ', @randBookTotal,') p '); SET @query1 = CONCAT(@query1, 'where c.id is not null'); PREPARE increased FROM @query1;EXECUTE increased; SET @startDate = DATE_ADD(@startDate, INTERVAL 1 DAY);END LOOP loop_label_p;END $$DELIMITER ;
总共会生成几十万或上百万条order数据；最好先简单加下index，不然query太慢，可以在创建db table后就加上。
添加index:
ALTER TABLE book ADD INDEX idx_unit_price(unit_price);ALTER TABLE customer_order ADD INDEX idx_order_no(no);ALTER TABLE customer_order ADD INDEX idx_order_date(order_date);ALTER TABLE customer_order ADD INDEX idx_quantity(quantity);
更新order no:
-- update order total_price-- please note it is better to add index first. otherwise it will be slow.-- update order_noupdate customer_orderset no = concat(REPLACE(LEFT(no, 16), '-', ''), customer_id, book_id)where no is not null;-- update total price
如果不想有重复的order no，可以通过下面的sql更新order no:
-- 处理重复的 order noupdate customer_order cojoin(select no from customer_order co2 group by co2.no having count(*) > 1) as cdoon co.no = cdo.noset co.no = concat(REPLACE(LEFT(uuid(), 16), '-', ''), customer_id, book_id);
如果还有重复的order no，继续run上面这个sql，直到没有重复的即可。
更新order表里的total_price:
-- update total priceupdate customer_order cojoin book bon co.book_id = b.idSET co.total_price = co.quantity * b.unit_price;
至此，我们的数据库表和对应的mock数据已经基本完成。使用mysqldump备份一下：
mysqldump -u [username] –p[password] [database_name] > [dump_file.sql]
下一步
视图（View）
存储过程（Store Procedure）
函数（Function）
触发器（Trigger）
定时任务（Job）
参考资料
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