fly on exercises

data/1.PostgreSQL初阶/2.PostgreSQL的安装/2.登录PostgreSQL/rds.json

@@ -2,5 +2,6 @@
   "type": "code_options",
   "author": "刘鑫",
   "source": "rds.md",
-  "notebook_enable": false
+  "notebook_enable": false,
+  "exercise_id": "6b04760cd212469c925eb4a9c4a66757"
 }
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-eeb777ca54434480a06bfe7fc5e7d3ca",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["primary_key.json","unique.json", "unique_2.json"]
 }
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/primary_key.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "primary_key.md",
+  "notebook_enable": false,
+  "exercise_id": "412c89270d24418ab35a1d919a5017e7"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/primary_key.md

+# 主键
+
+关于 PostgreSQL 的主键，哪一项是错误的？
+
+## 答案
+
+主键列只能是自增 id。
+
+## 选项
+
+### A
+
+主键隐含了聚集索引和唯一约束
+
+### B
+
+主键可以是一个字段，也可以是多个字段的组合
+
+### C
+
+语法约束上，可以允许无主键的表，但是从工程实践上，应该保持每个表都有正确的主键。
+
+### D
+
+主键或唯一键可以被引用为外键约束
+
+### E
+
+主键应可以唯一的标识数据，并且主键的一部分不应该依赖另一部分。
+

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/unique.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "unique.md",
+  "notebook_enable": false,
+  "exercise_id": "482896ba26ec43bc8ddedbf3448d47bb"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/unique.md

+# 唯一约束
+
+现有一个图书登记表：
+
+```postgresql
+create table book(
+    id serial primary key ,
+    title text,
+    publish_at date,
+    isbn text,
+    meta jsonb default '{}'::jsonb
+)
+```
+
+我们发现有时候客户可能会重复输入同一本书的信息，怎样约束用户不会输入同一本书？
+
+1. 删除id列，将isbn设置为主键
+2. 在 isbn 列上加唯一约束
+3. 执行 `create index on book(id, title, publish_at, isbn, meta)`
+4. 在 id 键上加唯一约束
+
+## 答案
+
+1 或者 2
+
+## 选项
+
+### A
+
+3
+
+### B
+
+4
+
+### C
+
+3 或 4
+
+### D
+
+3 和 4

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/unique_2.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "unique_2.md",
+  "notebook_enable": false,
+  "exercise_id": "f1f5779378ef4684a210188e5730b6a1"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/4.索引和约束/unique_2.md

+# 唯一约束
+
+现有一个图书登记表：
+
+```postgresql
+create table book(
+    id serial primary key ,
+    title text,
+    publish_at date,
+    isbn text,
+    meta jsonb default '{}'::jsonb
+)
+```
+
+我们发现有时候客户可能会重复输入同一本书的信息，*在不修改应用层程序的前提下*，怎样约束用户不会输入同一本书？
+
+1. 删除id列，将isbn设置为主键
+2. 在 isbn 列上加唯一约束
+3. 执行 `create index on book(id, title, publish_at, isbn, meta)`
+4. 在 id 键上加唯一约束
+
+## 答案
+
+2
+
+## 选项
+
+### A
+
+3
+
+### B
+
+4
+
+### C
+
+3 或 4
+
+### D
+
+3 和 4
+
+### E
+
+1 或 2
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/5. 触发器/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-a0cb78d68d814f5e935b41922b88e085",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["trigger.json"]
 }
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/5. 触发器/trigger.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "trigger.md",
+  "notebook_enable": false,
+  "exercise_id": "2724dfb0a71c473b8a071e1d2aecc030"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/5. 触发器/trigger.md

+# 触发器
+
+SmartMarket 公司的OA数据库中包含以下结构：
+
+```postgresql
+create table employee(
+    id serial primary key ,
+    name text,
+    dept text,
+    salary money,
+    meta jsonb default '{}'::jsonb
+);
+
+create table budget(
+    id serial primary key ,
+    dept text,
+    amount money
+)
+```
+
+我们省略了无关的内容。当某个员工的工资发生变动时，我们要修改他所在部门的预算。那么以下哪个选项可以解决问题？
+
+## 答案
+
+在 employee 表添加一个 after 触发器，当员工信息变动时，重算相关部门的预算。
+
+## 选项
+
+### A
+
+在 budget 表添加触发器，当员工信息变动时，重算相关部门的预算。
+
+### B
+
+将预算总额字段变成计算列，通过统计员工工资生成。
+
+### C
+
+将员工信息表的工资字段设置为部门预算总额的外键引用字段，并设置级联更新。
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/6.数据库扩展/extension.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "extension.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/6.数据库扩展/extension.md

+# 外部扩展
+
+下列哪个功能需要通过`create exension`语句安装扩展得到？
+
+## 答案
+
+postgis
+
+## 选项
+
+### A
+
+全文检索
+
+### B
+
+JSONB
+
+### C
+
+GIST 和 GIN 索引
+
+### D
+
+JSON Path 支持
+
+### E
+
+XML 和 XSLT 支持
+
+### F
+
+面向对象语法

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/6.数据库扩展/language.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "language.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/2.PostgreSQL中阶/1.PostgreSQL数据库的基本结构/6.数据库扩展/language.md

+# 过程语言
+
+关于 PostgreSQL PL 语言，错误的是：
+
+## 答案
+
+要安装新的扩展语言，需要重新编译 PostgreSQL 内核。
+
+## 选项
+
+### A
+
+PG 可以支持 Python、Perl、Lua 等多种 PL 语言编写函数。
+
+### B
+
+通过 create language 可以安装新的 pl 语言支持
+
+### C
+
+实现新的 PL 语言需要遵循 PostgreSQL 的语言扩展规范。
+
+### D
+
+用外部语言实现函数，要考虑跨边界传递数据的开销
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/1.聚合和分组/salary.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "salary.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/1.聚合和分组/salary.md

+# 工资最高的人
+
+现有员工信息表如下：
+
+```postgresql
+create table employee
+(
+    id     serial primary key,
+    name   text,
+    dept   text,
+    salary money
+);
+```
+
+下面哪条查询，可以给出每个部门工资最高的员工的 id, name, dept, salary 四项信息？
+
+## 答案
+
+```postgresql
+select l.id, l.name, l.dept, l.salary
+from employee as l
+         join (select max(salary) as salary, dept
+               from employee
+               group by dept) as r
+              on l.dept = r.dept and l.salary = r.salary
+```
+
+## 选项
+
+### select 与 group by 不匹配
+
+```postgresql
+select id, name, dept, max(salary) from employee group by dept;
+```
+
+### group by 不对
+
+```postgresql
+select id, name, dept, max(salary) from employee group by dept, id, name;
+```
+
+### group by 不对
+
+```postgresql
+select id, name, dept, max(salary) from employee group by dept, id, name having salary = max(salary);
+```
+
+### 结构错误
+
+### group by 不对
+
+```postgresql
+select id, name, dept, max(salary) from employee where salary=max(salary) group by dept;
+```
+

data/2.PostgreSQL中阶/2.服务端编程/3.子查询/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-55fd213f919d411c9b572241c4bb7807",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["subquery.json"]
 }
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/3.子查询/subquery.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "subquery.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/3.子查询/subquery.md

+# 子查询
+
+现有员工表
+
+```postgresql
+create table employee(
+    id serial primary key ,
+    name text,
+    dept text,
+    salary money
+)
+```
+
+我们希望找出比销售部（dept 为 sale）工资最高的员工工资更高的那部分人，查询出他们的完整信息，下面哪一项可以满足要求？
+
+## 答案
+
+```postgresql
+select id, name, dept, salary 
+from employee
+where salary > (select max(salary) from employee where dept='sale')
+```
+
+## 选项
+
+### A
+
+```postgresql
+select id, name, dept, salary 
+from employee
+where dept = 'sale'
+group by dept having salary > max(salary)
+```
+
+### B
+
+```postgresql
+select l.id, l.name, l.dept, l.salary 
+from employee as l join employee as r on l.salary > max(r.salary)
+where r.dept = 'sale' 
+group by r.dept 
+```
+
+### C
+
+```postgresql
+select id, name, dept, salary 
+from employee
+having salary > (select max(salary) from employee where dept='sale')
+```
+
+
+

data/2.PostgreSQL中阶/2.服务端编程/6.DML/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-e1cd59819dd74a0bacc707f7863aad53",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["insert.json", "update.json", "delete.json"]
 }
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/6.DML/delete.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "delete.md",
+  "notebook_enable": false,
+  "exercise_id": "78e6ca15ba794ef3b2092de4640308b9"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/6.DML/delete.md

+# 删除
+
+SmartMarket 公司的业务数据库中，有一个 orders 表，其结构主要是以下形态：
+
+```postgresql
+create table orders
+(
+    id         serial primary key,
+    meta       jsonb     default '{}'::jsonb,
+    content    jsonb     default '{}'::jsonb,
+    created_at timestamp default now(),
+    deal       boolean
+)
+```
+
+有一个业务系统会实时的将已经成交（deal 字段为 true）的订单数据转储，现在我们仅需要一个清理 程序，将已经成 交的数据从 orders 表删除并记录被删除的数据id。下面哪个操作是对的？
+
+## 答案
+
+在一个独立的定时任务中执行
+
+```postgresql
+delete
+from orders
+where deal
+returning id;
+```
+
+并记录id
+
+## 选项
+
+### A
+
+在一个独立的定时任务中执行
+
+```postgresql
+truncate orders;
+```
+
+### B
+
+在一个独立的定时任务中执行
+
+```postgresql
+delete
+from orders;
+```
+
+### C
+
+在一个独立的定时任务中执行
+
+```postgresql
+drop table orders;
+create table orders
+(
+    id         serial primary key,
+    meta       jsonb     default '{}'::jsonb,
+    content    jsonb     default '{}'::jsonb,
+    created_at timestamp default now(),
+    deal       boolean
+);
+```
+
+### D
+
+建立视图
+
+```postgresql
+create view order_view as
+select id, meta, content, created_at
+from orders
+where not deal;
+```
+
+并要求业务系统只能访问这个视图。
+
+### E
+
+在一个独立的定时任务中执行
+
+```postgresql
+delete
+from orders
+where deal;
+```
+
+并记录操作前后表中的最大 id
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/6.DML/insert.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "insert.md",
+  "notebook_enable": false,
+  "exercise_id": "2d562e3ae4a84e648de31452a67ba71f"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/6.DML/insert.md

+# 插入
+
+现有一个表：
+
+```postgresql
+create table book(
+    id serial primary key ,
+    title text not null ,
+    meta jsonb default '{}'::jsonb,
+    price money,
+    isbn text not null ,
+    publish_at date not null 
+);
+create unique index on book(isbn);
+create index on book using gin(meta);
+```
+
+那么下列哪个选项的代码可以执行成功？
+
+## 答案
+
+```postgresql
+insert into book(title, price, isbn, publish_at) select 'a book title', 25.4, 'xx-xxxx-xxxx', '2019-12-1'::date;
+insert into book(title, price, isbn, publish_at) select 'a other book title', 25.4, 'yy-yyyy-xxxx', '2019-12-1'::date; 
+```
+
+## 选项
+
+### 唯一键冲突
+
+```postgresql
+insert into book(title, price, isbn, publish_at) select 'a book title', 25.4, 'xx-xxxx-xxxx', '2019-12-1'::date;
+insert into book(title, price, isbn, publish_at) select 'a other book title', 35.4, 'xx-xxxx-xxxx', '2019-12-1'::date; 
+```
+
+### 缺少必要的列
+
+```postgresql
+insert into book(price, isbn, publish_at) select 25.4, 'xx-xxxx-xxxx', '2019-12-1'::date;
+insert into book(price, isbn, publish_at) select 35.4, 'yy-yyyy-xxxx', '2019-12-1'::date;
+```
+
+### 类型错误
+
+```postgresql
+insert into book(title, price, isbn, publish_at) select 'a book title', 'unknown', 'xx-xxxx-xxxx', '2019-12-1'::date;
+insert into book(title, price, isbn, publish_at) select 'a other book title', 'unknown', 'xx-xxxx-xxxx', '2019-12-1'::date;
+```
+
+### 违反非空约束
+
+```postgresql
+insert into book(title, price, isbn, publish_at) select null, 'unknown', 'xx-xxxx-xxxx', '2019-12-1'::date;
+insert into book(title, price, isbn, publish_at) select null, 'unknown', 'xx-xxxx-xxxx', '2019-12-1'::date;
+```

data/2.PostgreSQL中阶/2.服务端编程/6.DML/update.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "update.md",
+  "notebook_enable": false,
+  "exercise_id": "d6f2c270c3cd41a499715e55a2c565ba"
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/6.DML/update.md

+# 更新数据
+
+现有 employee 表如下：
+
+```postgresql
+create table employee
+(
+    id serial primary key,
+    name text,
+    dept text,
+    salary money
+);
+```
+
+我们希望修改销售部(dept 字段为 sale)员工 Dora Muk 的工资，将其增加 1000，返回她的工号。正确的修改语句是：
+
+## 答案
+
+```postgresql
+update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora Muk' returning id;
+```
+
+## 选项
+
+### 过滤条件不严谨
+
+```postgresql
+update employee set salary = salary + 1000 where name = 'Dora Muk' returning id;
+```
+
+### 没有返回员工id
+
+```postgresql
+update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora Muk';
+```
+
+
+### 缺少过滤条件
+
+```postgresql
+update employee set salary = salary + 1000 returning id;
+```
+
+### 错误的赋值语句
+
+```postgresql
+update employee set salary += 1000 returning id;
+```
+

data/2.PostgreSQL中阶/2.服务端编程/7.过程化编程/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-eb4048b7dfd3469f8049330ba78427b5",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["loop.json"]
 }
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/7.过程化编程/loop.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "loop.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/2.PostgreSQL中阶/2.服务端编程/7.过程化编程/loop.md

+# 循环
+
+下面哪一项定义的函数可以生成指定范围内的整数数列？
+
+## 答案
+
+```postgresql
+create function gen(start integer, stop integer) returns setof integer as $$
+begin 
+    for idx in start .. stop loop
+        return next idx;
+    end loop;
+end;
+$$ language plpgsql;
+```
+
+## 选项
+
+### A
+
+```postgresql
+create function gen(start integer, stop integer) returns integer as $$
+begin 
+    for idx in start .. stop loop
+        return idx;
+    end loop;
+end;
+$$ language plpgsql;
+```
+
+### B
+
+```postgresql
+create function gen(start integer, stop integer) returns integer as $$
+begin 
+    for idx in start .. stop loop
+        yield idx;
+    end loop;
+end;
+$$ language plpgsql;
+```
+
+### C
+
+```postgresql
+create function gen(start integer, stop integer) returns setof integer as $$
+begin 
+    for idx in start .. stop loop
+        return idx;
+        idx += 1;
+    end loop;
+end;
+$$ language plpgsql;
+```
+
+### D
+
+```postgresql
+create function gen(start integer, stop integer) returns setof integer as $$
+begin 
+    for idx in start .. stop loop
+        select idx;
+    end loop ;
+end;
+$$ language plpgsql;
+```
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/2.透视表 /config.json

+{
+  "node_id": "pg-693a81467f444886a199bac681f238b8",
+  "keywords": [],
+  "children": [],
+  "export": ["pivot.json"]
+}
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/2.透视表 /pivot.md

+# 透视表
+
+现有销售记录表
+
+```postgresql
+create table sales(
+    id serial primary key ,
+    sku_id integer not null ,
+    amount money,
+    meta jsonb default '{}'::jsonb,
+    created_at timestamp default now()
+);
+create index on sales(created_at);
+```
+
+现在我们希望对这个表做一个月度的透视汇总，得到2020年每个月每种商品(sku_id)的的销售总额，每个月一列，哪一项可以实现？
+
+## 答案
+
+```postgresql
+select sku_id, 
+       sum(case extract(month from created_at) when 1 then amount else 0::money end) as Jan,
+       sum(case extract(month from created_at) when 2 then amount else 0::money end) as Feb,
+       sum(case extract(month from created_at) when 3 then amount else 0::money end) as Mar,
+       sum(case extract(month from created_at) when 4 then amount else 0::money end) as Apr,
+       sum(case extract(month from created_at) when 5 then amount else 0::money end) as May,
+       sum(case extract(month from created_at) when 6 then amount else 0::money end) as June,
+       sum(case extract(month from created_at) when 7 then amount else 0::money end) as July,
+       sum(case extract(month from created_at) when 8 then amount else 0::money end) as Aug,
+       sum(case extract(month from created_at) when 9 then amount else 0::money end) as Sept,
+       sum(case extract(month from created_at) when 10 then amount else 0::money end) as Oct,
+       sum(case extract(month from created_at) when 11 then amount else 0::money end) as Nov,
+       sum(case extract(month from created_at) when 12 then amount else 0::money end) as Dec
+from sales
+where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
+group by sku_id; 
+```
+
+## 选项
+
+### 格式不相符
+
+```postgresql
+select sku_id, extract(month from created_at) as month, sum(amount) 
+from sales
+where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
+group by 1, 2; 
+```
+
+### 计算逻辑错误
+
+```postgresql
+select sku_id, 
+       sum(amount) as Jan,
+       sum(amount) as Feb,
+       sum(amount) as Mar,
+       sum(amount) as Apr,
+       sum(amount) as May,
+       sum(amount) as June,
+       sum(amount) as July,
+       sum(amount) as Aug,
+       sum(amount) as Sept,
+       sum(amount) as Oct,
+       sum(amount) as Nov,
+       sum(amount) as Dec
+from sales
+where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
+group by sku_id, extract(month from created_at); 
+```
+
+### 计算格式错误
+
+```postgresql
+select sku_id, 
+       sum(amount having extract(month from created_at) = 1) as Jan,
+       sum(amount having extract(month from created_at) = 2) as Feb,
+       sum(amount having extract(month from created_at) = 3) as Mar,
+       sum(amount having extract(month from created_at) = 4) as Apr,
+       sum(amount having extract(month from created_at) = 5) as May,
+       sum(amount having extract(month from created_at) = 6) as June,
+       sum(amount having extract(month from created_at) = 7) as July,
+       sum(amount having extract(month from created_at) = 8) as Aug,
+       sum(amount having extract(month from created_at) = 9) as Sept,
+       sum(amount having extract(month from created_at) = 10) as Oct,
+       sum(amount having extract(month from created_at) = 11) as Nov,
+       sum(amount having extract(month from created_at) = 12) as Dec
+from sales
+where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
+group by sku_id, extract(month from created_at); 
+```
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/2.写入和冲突/config.json → data/3.PostgreSQL高阶/3.SQL高级技巧/3.写入和冲突/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-6ce3520f7a67494a90378e7b194f8720",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["score.json"]
 }
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/3.写入和冲突/score.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "score.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/3.写入和冲突/score.md

+# 积分累计
+
+现有一个表
+
+```postgresql
+create table book_in(
+    login integer primary key ,
+    score integer default 0
+);
+```
+
+用于记录用户行为积分，不同的客户端分布式的异步提交各个login的行为得分，如果一个用户不在表中，我们
+需要插入一条新纪录，如果已经存在，则需要将新提交的score累加到表中，下列哪个查询可以实现此功能？
+
+## 答案
+
+```postgresql
+insert into book_in(login, score) values ($1, $2) on conflict do update set score=$2;
+```
+
+## 选项
+
+### A
+
+```postgresql
+try
+    insert into book_in(login, score) values ($1, $2);
+catch
+    update book_in set score = $2 where login = $1
+finally
+    commit;
+```
+
+### B
+
+```postgresql
+insert into book_in(login, score) select $1, $2;
+```
+
+### C
+
+```postgresql
+replace book_in(login, score) select $1, $2;
+```
+
+### D
+
+```postgresql
+upsert into book_in(login, score) select $1, $2;
+```

data/3.PostgreSQL高阶/3.SQL高级技巧/3.事务/config.json → data/3.PostgreSQL高阶/3.SQL高级技巧/4.事务/config.json

@@ -2,5 +2,5 @@
   "node_id": "pg-2d547e778fc4453b84feb0a0c6341348",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": ["transaction.json"]
 }
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/4.事务/transaction.json

+{
+  "type": "code_options",
+  "author": "刘鑫",
+  "source": "transaction.md",
+  "notebook_enable": false
+}
\ No newline at end of file

data/3.PostgreSQL高阶/3.SQL高级技巧/4.事务/transaction.md

+# 事务
+
+现有 test1 表如下
+
+```postgresql
+create table test1(a integer primary key );
+```
+
+我们执行下面的语句
+
+```postgresql
+CREATE PROCEDURE transaction_test1()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    FOR i IN 0..9 LOOP
+        INSERT INTO test1 (a) VALUES (i);
+        IF i % 2 = 0 THEN
+            COMMIT;
+        ELSE
+            ROLLBACK;
+        END IF;
+    END LOOP;
+END;
+$$;
+
+CALL transaction_test1();
+```
+
+时，下面哪一项的解释是对的？
+
+## 答案
+
+每当循环迭代到偶数的时候提交插入，最终 test1 表中是`0,2,4,6,8`。
+
+## 选项
+
+### A
+
+以最后一次提交为准，最终 test1 表中是 0 到 9 共九个数字。
+
+### B
+
+所有插入都回滚了。test1 表中没有数据。
+
+### C
+
+这个过程执行会报错。
\ No newline at end of file

data/tree.json

@@ -313,6 +313,13 @@
                       "children": []
                     }
                   },
+                  {
+                    "透视表 ": {
+                      "node_id": "pg-693a81467f444886a199bac681f238b8",
+                      "keywords": [],
+                      "children": []
+                    }
+                  },
                   {
                     "写入和冲突": {
                       "node_id": "pg-6ce3520f7a67494a90378e7b194f8720",