# SCHEMA 的 KV 映射原理（C）

+ 聚簇表案例 - 创建聚簇表 User
```
CREATE TABLE User (
    ID int not null PRIMARY KEY ~!@clustered@!~,
    Name varchar(20),
    Role varchar(20),
    Age int,
    KEY idxAge (Age)
);
```
+ (ID 列为主键列，聚簇列)

+ 插入 3 行数据
```
Insert into User values ( 1, "TiDB", "SQL Layer", 10);
Insert into User values (2, "TiKV", "KV Engine", 20);
Insert into User values (3, "PD", "Manager", 30);
```

+ 数据的 KV 映射关系
```
t10_r1 --> ["TiDB", "SQL Layer", 10]
t10_r2 --> ["TiKV", "KV Engine", 20]
t10_r3 --> ["PD", "Manager", 30]
```
-------------------------------------------------------------
CREATE TABLE User (
    ID int not null PRIMARY KEY Clustered,
    Name varchar(20),
    Role varchar(20),
    Age int,
    KEY idxAge (Age)
);

1, "TiDB", "SQL Layer", 10
2, "TiKV", "KV Engine", 20
3, "PD", "Manager", 30

t10_r1 --> ["TiDB", "SQL Layer", 10]
t10_r2 --> ["TiKV", "KV Engine", 20]
t10_r3 --> ["PD", "Manager", 30]