重构章节顺序

data/3.MySQL高阶/5.设计优化/2. 范式设计/config.json

+{
+  "node_id": "mysql-bee8db3dd5354a42bb50277fe4cb2913",
+  "keywords": [],
+  "children": [],
+  "export": [
+    "customer_order.json"
+  ],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 2
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/2. 范式设计/customer_order.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "customer_order.md",
+  "notebook_enable": false,
+  "exercise_id": "37f64868b412458c8c584a7ab7941792"
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/2. 范式设计/customer_order.md

+# 客户和订单
+
+Goods 中有客户/订单系统如下：
+
+```mysql
+create table customers
+(
+    id           serial primary key,
+    company_name varchar(256),
+    address      varchar(1024),
+    city         varchar(256),
+    state        varchar(256)
+);
+
+create table products
+(
+    id          serial primary key,
+    description varchar(1024),
+    unit_price  decimal(12, 4)
+);
+
+create table orders
+(
+    id          serial primary key,
+    product_id  integer references products (id),
+    order_date  timestamp,
+    quantity    integer,
+    customer_id integer references customers(id)
+);
+
+```
+
+我们希望这个数据库能够允许每个订单包含多种商品，那么应该如何改造？
+
+## 答案
+
+* 添加一个 order_detail 表，引用 order id、product id，增加 quantity 列
+* order 表中删除 product id 和 quantity 列
+
+## 选项
+
+### A
+
+将 order 表的修改为以 product id 和 customer id 作为联合主键
+
+### B
+
+删除 orders 表中的 product id 和 quantity 列
+
+### C
+
+在 order 表的主键上加唯一约束
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/3.反范式设计/config.json

+{
+  "node_id": "mysql-3e4c837b471c454c90bfbc32445f2780",
+  "keywords": ["反范式", "anti pattern"],
+  "children": [],
+  "export": [
+    "slack.json"
+  ],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/3.反范式设计/slack.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "slack.md",
+  "notebook_enable": false,
+  "exercise_id": "d62e33f550494f849f87b62acdcf9d0a"
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/3.反范式设计/slack.md

+# 反范式设计
+
+反范式优化的主要动机和思路是：
+
+1. 通过适当增加冗余字段，减少连接查询的次数和复杂度
+2. 对于经常发生的聚合计算，如果对实时正确性要求不高，可以缓存中间结果，减少实时的聚合计算压力
+3. 用适度的写冗余，换取读操作的大幅优化
+4. 适当的放宽索引，可以优化局限于少数字段的查询性能
+
+## 答案
+
+全部都是
+
+## 选项
+
+### A
+
+全部都不对
+
+### B
+
+```
+1, 2, 3
+```
+
+### C
+
+```
+2, 3, 4
+```
+
+### D
+
+```
+2, 3
+```
+
+### E
+
+```
+3, 4
+```
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/4.增加中间表/config.json

+{
+  "node_id": "mysql-a2ddae1b044149ecbb74db3b6eb32721",
+  "keywords": [
+    "middle",
+    "中间表"
+  ],
+  "children": [],
+  "export": [
+    "daily_payment2.json"
+  ],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/4.增加中间表/daily_payment2.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "daily_payment2.md",
+  "notebook_enable": false,
+  "exercise_id": "71343fd41e5d4af5a5876849e77a3be2"
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/4.增加中间表/daily_payment2.md

+# 每日报表优化
+
+# 每日报表
+
+分析过去一段时间的查询数据，Joe 发现 payment 表
+```mysql
+create table payment(
+    payment_id int primary key auto_increment,
+    customer_id int,
+    staff_id int,
+    rental_id int,
+    amount decimal(12, 4),
+    payment_date timestamp
+)
+```
+每天的订单量很大，下面这个查询的统计过程占用了大多数数据库资源，查询不会
+早于当天，总是在历史上某一个日期段内查询
+
+```mysql
+select date(payment_date) as day, sum(amount)
+from payment
+where date(payment_date) between $1 and $2
+group by date(payment_date);
+```
+
+
+怎样优化最有效？
+
+##  答案
+
+建立中间表并建立索引。
+
+```postgresql
+create table daily_payment(day date primary key , amount decimal(12, 4));
+
+insert into daily_payment(day, amount) 
+select payment_date::date as day, sum(amount) as amount from payment group by day;
+
+```
+
+使用
+
+```mysql
+select day, amount from view_daily_payment where day between $1 and $2;
+```
+
+进行查询。并且每天定时执行一次刷新命令
+
+```mysql
+insert into daily_payment(day, amount)
+select date(payment_date) as day, sum(amount) as amount 
+from payment
+where date(payment_date) between DATE_SUB(CURDATE(), INTERVAL 2 DAY) and DATE_SUB(CURDATE(), INTERVAL 1 DAY) 
+group by day;
+
+```
+
+## 选项
+
+### 不会优化 sum 和 group by
+
+在 payment_date 列上建立索引
+
+```mysql
+create index idx_payment_date on payment(payment_date);
+```
+
+### 不会优化 sum
+
+建立计算列
+
+```mysql
+alter table payment add day date generated always as ( payment_date::date ) stored 
+```
+
+然后使用它改写查询
+
+```mysql
+select day as day, sum(amount)
+from payment
+where day between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
+group by day;
+```
+
+### 优化了日期查询，但是不会优化统计过程
+
+建立表达式索引
+
+```mysql
+create index idx_payment_day on payment((date(payment_date)));
+```
+
+### 不做物化，对查询速度不会有显著改善
+
+建立视图
+
+```mysql
+create view view_daily_payment as select date(payment_date) as day, amount from payment;
+```
+
+然后在视图 view_daily_payment 上执行
+
+```mysql
+select day, sum(amount) 
+from view_daily_payment
+where day between $1 and date('yesterday')
+group by day 
+```
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/5.分析数据表/config.json

+{
+  "node_id": "mysql-cde6eae01784468fa0171ff3042f221f",
+  "keywords": ["analyze table", "分析数据表"],
+  "children": [],
+  "export": [],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/6.检查数据表/config.json

+{
+  "node_id": "mysql-fbcc654d6a86452aa349d2ed6003adb6",
+  "keywords": ["show profile"],
+  "children": [],
+  "export": [],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/7.优化数据表/config.json

+{
+  "node_id": "mysql-f5775462ae784d44a4b2bce5f456311a",
+  "keywords": ["performance table", "优化数据表"],
+  "children": [],
+  "export": [],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/3.MySQL高阶/5.设计优化/8.拆分数据表/config.json

+{
+  "node_id": "mysql-ccb6fcf2983b4b3e8b37abbcbc776f21",
+  "keywords": [],
+  "children": [],
+  "export": [],
+  "keywords_must": [],
+  "keywords_forbid": [],
+  "group": 0
+}
\ No newline at end of file

data/tree.json

@@ -19,13 +19,13 @@
                 ],
                 "children": [
                   {
-                    "数据库基本概念": {
-                      "node_id": "mysql-8e971f3c569a4e56bb83b5d75a2a425f",
+                    "MySQL 基本概念": {
+                      "node_id": "mysql-925f9d57c7794e5391fb790bcdbf43c6",
                       "keywords": [],
                       "children": [],
                       "keywords_must": [
                         [
-                          "数据库",
+                          "mysql",
                           "概念"
                         ]
                       ],
@@ -34,13 +34,13 @@
                     }
                   },
                   {
-                    "MySQL 基本概念": {
-                      "node_id": "mysql-925f9d57c7794e5391fb790bcdbf43c6",
+                    "数据库基本概念": {
+                      "node_id": "mysql-8e971f3c569a4e56bb83b5d75a2a425f",
                       "keywords": [],
                       "children": [],
                       "keywords_must": [
                         [
-                          "mysql",
+                          "数据库",
                           "概念"
                         ]
                       ],