数据库基础

数据库：保存有组织的数据的容器。

基础知识(1-2章)

无法直接访问数据库，必须使用MySQL等数据库管理系统(DBMS)来创建与操纵数据库。

表：某种特定类型数据的结构化清单。(一种类型的数据)

相同数据库中不能两次使用相同的表名。

模式：关于数据库和表的布局及特性的信息。如可以存储什么样的数据、数据如何分解、各部分信息如何命名等，描述表的这组信息就是所谓的模式，模式可以用来描述数据库中特定的表以及整个数据库(和其中的表的关系)。

列：表中的一个字段。所有表都是由一个或多个列组成的。

行：表中的一个记录。表中的数据按行存储，所保存的每个记录存储在自己的行内。

主键：一列或一组列，其值能够唯一区分表中每个行。

• 任意两行都不具有相同的主键值
• 每个行都必须具有一个主键值(不允许NULL值)

好习惯:

• 不更新主键列中的值
• 不重用主键列的值
• 不在主键列中使用可能会更改的值

SQL：结构化查询语言，一种专门用来与数据库通信的语言

不是某个特定数据库的专利语言，任意两个DBMS实现的SQL都不完全相同。

DBMS分两类：

• 基于共享文件系统的DBMS，用于桌面用途，通常不用于高端或更关键的应用。(如Microsoft Access和FileMaker)
• 基于客户机-服务器的DBMS，服务器部分负责所有数据的访问和处理，运行在数据库服务器上，与数据打交道的只有服务器软件，客户机是与用户打交道的软件。(如MySQL、Oracle、Microsoft SQL Server等)

客户机与服务器软件可以安装在一台或者多台计算机上，用户不能直接访问数据文件。

数据类型(附录D)

数据类型：一个列中所容许的数据的类型。

• 每个表列都有相应的数据类型，它限制该列中存储的数据。
• 数据类型允许在内部更有效地存储数据。如可以用一种比文本串更简洁的格式存储数值和日期时间值。
• 数据类型允许变换排序顺序。如1、10、2作为串处理和作为数值处理排序不同。

串数据类型

定长串：接受固定长度的字符串，长度在创建表时指定。如CHAR

变长串：存储可变长度的文本。如TEXT

变长串更灵活，但处理时间长且不可被索引；定长串处理速度快且可被索引。

串必须括在引号内，最好是单引号。

数值数据类型

使用UNSIGNED关键字后只能存储正数，取值范围翻倍。

数值不应该括在引号内。

MySQL中没有专门存储货币的数据类型，一般情况下使用DECIMAL(8,2)。

日期与时间数据类型

二进制数据类型

二进制数据类型可以存储任何数据(甚至包括二进制信息)，如图像、多媒体、字处理文档等。

MySQL必知必会中使用的数据库

########################
# Create customers table
########################
CREATE TABLE customers
(
  cust_id      int       NOT NULL AUTO_INCREMENT,
  cust_name    char(50)  NOT NULL ,
  cust_address char(50)  NULL ,
  cust_city    char(50)  NULL ,
  cust_state   char(5)   NULL ,
  cust_zip     char(10)  NULL ,
  cust_country char(50)  NULL ,
  cust_contact char(50)  NULL ,
  cust_email   char(255) NULL ,
  PRIMARY KEY (cust_id)
) ENGINE=InnoDB;

#########################
# Create orderitems table
#########################
CREATE TABLE orderitems
(
  order_num  int          NOT NULL ,
  order_item int          NOT NULL ,
  prod_id    char(10)     NOT NULL ,
  quantity   int          NOT NULL ,
  item_price decimal(8,2) NOT NULL ,
  PRIMARY KEY (order_num, order_item)
) ENGINE=InnoDB;


#####################
# Create orders table
#####################
CREATE TABLE orders
(
  order_num  int      NOT NULL AUTO_INCREMENT,
  order_date datetime NOT NULL ,
  cust_id    int      NOT NULL ,
  PRIMARY KEY (order_num)
) ENGINE=InnoDB;

#######################
# Create products table
#######################
CREATE TABLE products
(
  prod_id    char(10)      NOT NULL,
  vend_id    int           NOT NULL ,
  prod_name  char(255)     NOT NULL ,
  prod_price decimal(8,2)  NOT NULL ,
  prod_desc  text          NULL ,
  PRIMARY KEY(prod_id)
) ENGINE=InnoDB;

######################
# Create vendors table
######################
CREATE TABLE vendors
(
  vend_id      int      NOT NULL AUTO_INCREMENT,
  vend_name    char(50) NOT NULL ,
  vend_address char(50) NULL ,
  vend_city    char(50) NULL ,
  vend_state   char(5)  NULL ,
  vend_zip     char(10) NULL ,
  vend_country char(50) NULL ,
  PRIMARY KEY (vend_id)
) ENGINE=InnoDB;

###########################
# Create productnotes table
###########################
CREATE TABLE productnotes
(
  note_id    int           NOT NULL AUTO_INCREMENT,
  prod_id    char(10)      NOT NULL,
  note_date datetime       NOT NULL,
  note_text  text          NULL ,
  PRIMARY KEY(note_id),
  FULLTEXT(note_text)
) ENGINE=MyISAM;


#####################
# Define foreign keys
#####################
ALTER TABLE orderitems ADD CONSTRAINT fk_orderitems_orders FOREIGN KEY (order_num) REFERENCES orders (order_num);
ALTER TABLE orderitems ADD CONSTRAINT fk_orderitems_products FOREIGN KEY (prod_id) REFERENCES products (prod_id);
ALTER TABLE orders ADD CONSTRAINT fk_orders_customers FOREIGN KEY (cust_id) REFERENCES customers (cust_id);
ALTER TABLE products ADD CONSTRAINT fk_products_vendors FOREIGN KEY (vend_id) REFERENCES vendors (vend_id);

##########################
# Populate customers table
##########################
INSERT INTO customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES(10001, 'Coyote Inc.', '200 Maple Lane', 'Detroit', 'MI', '44444', 'USA', 'Y Lee', 'ylee@coyote.com');
INSERT INTO customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
VALUES(10002, 'Mouse House', '333 Fromage Lane', 'Columbus', 'OH', '43333', 'USA', 'Jerry Mouse');
INSERT INTO customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES(10003, 'Wascals', '1 Sunny Place', 'Muncie', 'IN', '42222', 'USA', 'Jim Jones', 'rabbit@wascally.com');
INSERT INTO customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES(10004, 'Yosemite Place', '829 Riverside Drive', 'Phoenix', 'AZ', '88888', 'USA', 'Y Sam', 'sam@yosemite.com');
INSERT INTO customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
VALUES(10005, 'E Fudd', '4545 53rd Street', 'Chicago', 'IL', '54545', 'USA', 'E Fudd');


########################
# Populate vendors table
########################
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1001,'Anvils R Us','123 Main Street','Southfield','MI','48075', 'USA');
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1002,'LT Supplies','500 Park Street','Anytown','OH','44333', 'USA');
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1003,'ACME','555 High Street','Los Angeles','CA','90046', 'USA');
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1004,'Furball Inc.','1000 5th Avenue','New York','NY','11111', 'USA');
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1005,'Jet Set','42 Galaxy Road','London', NULL,'N16 6PS', 'England');
INSERT INTO vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES(1006,'Jouets Et Ours','1 Rue Amusement','Paris', NULL,'45678', 'France');


#########################
# Populate products table
#########################
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('ANV01', 1001, '.5 ton anvil', 5.99, '.5 ton anvil, black, complete with handy hook');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('ANV02', 1001, '1 ton anvil', 9.99, '1 ton anvil, black, complete with handy hook and carrying case');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('ANV03', 1001, '2 ton anvil', 14.99, '2 ton anvil, black, complete with handy hook and carrying case');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('OL1', 1002, 'Oil can', 8.99, 'Oil can, red');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('FU1', 1002, 'Fuses', 3.42, '1 dozen, extra long');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('SLING', 1003, 'Sling', 4.49, 'Sling, one size fits all');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('TNT1', 1003, 'TNT (1 stick)', 2.50, 'TNT, red, single stick');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('TNT2', 1003, 'TNT (5 sticks)', 10, 'TNT, red, pack of 10 sticks');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('FB', 1003, 'Bird seed', 10, 'Large bag (suitable for road runners)');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('FC', 1003, 'Carrots', 2.50, 'Carrots (rabbit hunting season only)');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('SAFE', 1003, 'Safe', 50, 'Safe with combination lock');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('DTNTR', 1003, 'Detonator', 13, 'Detonator (plunger powered), fuses not included');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('JP1000', 1005, 'JetPack 1000', 35, 'JetPack 1000, intended for single use');
INSERT INTO products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('JP2000', 1005, 'JetPack 2000', 55, 'JetPack 2000, multi-use');



#######################
# Populate orders table
#######################
INSERT INTO orders(order_num, order_date, cust_id)
VALUES(20005, '2005-09-01', 10001);
INSERT INTO orders(order_num, order_date, cust_id)
VALUES(20006, '2005-09-12', 10003);
INSERT INTO orders(order_num, order_date, cust_id)
VALUES(20007, '2005-09-30', 10004);
INSERT INTO orders(order_num, order_date, cust_id)
VALUES(20008, '2005-10-03', 10005);
INSERT INTO orders(order_num, order_date, cust_id)
VALUES(20009, '2005-10-08', 10001);


###########################
# Populate orderitems table
###########################
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 1, 'ANV01', 10, 5.99);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 2, 'ANV02', 3, 9.99);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 3, 'TNT2', 5, 10);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 4, 'FB', 1, 10);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20006, 1, 'JP2000', 1, 55);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 1, 'TNT2', 100, 10);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 1, 'FC', 50, 2.50);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 1, 'FB', 1, 10);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 2, 'OL1', 1, 8.99);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 3, 'SLING', 1, 4.49);
INSERT INTO orderitems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 4, 'ANV03', 1, 14.99);

#############################
# Populate productnotes table
#############################
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(101, 'TNT2', '2005-08-17',
'Customer complaint:
Sticks not individually wrapped, too easy to mistakenly detonate all at once.
Recommend individual wrapping.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(102, 'OL1', '2005-08-18',
'Can shipped full, refills not available.
Need to order new can if refill needed.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(103, 'SAFE', '2005-08-18',
'Safe is combination locked, combination not provided with safe.
This is rarely a problem as safes are typically blown up or dropped by customers.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(104, 'FC', '2005-08-19',
'Quantity varies, sold by the sack load.
All guaranteed to be bright and orange, and suitable for use as rabbit bait.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(105, 'TNT2', '2005-08-20',
'Included fuses are short and have been known to detonate too quickly for some customers.
Longer fuses are available (item FU1) and should be recommended.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(106, 'TNT2', '2005-08-22',
'Matches not included, recommend purchase of matches or detonator (item DTNTR).'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(107, 'SAFE', '2005-08-23',
'Please note that no returns will be accepted if safe opened using explosives.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(108, 'ANV01', '2005-08-25',
'Multiple customer returns, anvils failing to drop fast enough or falling backwards on purchaser. Recommend that customer considers using heavier anvils.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(109, 'ANV03', '2005-09-01',
'Item is extremely heavy. Designed for dropping, not recommended for use with slings, ropes, pulleys, or tightropes.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(110, 'FC', '2005-09-01',
'Customer complaint: rabbit has been able to detect trap, food apparently less effective now.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(111, 'SLING', '2005-09-02',
'Shipped unassembled, requires common tools (including oversized hammer).'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(112, 'SAFE', '2005-09-02',
'Customer complaint:
Circular hole in safe floor can apparently be easily cut with handsaw.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(113, 'ANV01', '2005-09-05',
'Customer complaint:
Not heavy enough to generate flying stars around head of victim. If being purchased for dropping, recommend ANV02 or ANV03 instead.'
);
INSERT INTO productnotes(note_id, prod_id, note_date, note_text)
VALUES(114, 'SAFE', '2005-09-07',
'Call from individual trapped in safe plummeting to the ground, suggests an escape hatch be added.
Comment forwarded to vendor.'
);

图形化效果：

customers表：

orderitems表：

orders表：

productnotes表：

vendors表：

products表：