# Example

+ Non-clustered table - Create non-clustered table User
+ ID column is the primary key column, non-clustered column
+ Insert 3 rows of data
```
...
PRIMARY KEY ~!@NONClustered@!~,
...
Insert into User values ( 100, "TiDB", "SQL Layer", 10 );
Insert into User values ( 200, "TiKV", "KV Engine", 20 );
Insert into User values ( 300, "PD", "Manager", 30 );
t10_i1_100 --> 1
t10_i1_200 --> 2
t10_i1_300 --> 3
```

------------------------------------------------------------
Assume that a user table is stored in TiDB

```
CREATE TABLE User (
    ID int not null PRIMARY KEY NONClustered,
    Name varchar(20),
    Role varchar(20),
    Age int,
    KEY idxAge (Age)
);
```

3 rows of data inserted
```
100, "TiDB", "SQL Layer", 10
200, "TiKV", "KV Engine", 20
300, "PD", "Manager", 30
```

KV mapping relationships of data
```
t10_r1 --> [100, "TiDB", "SQL Layer", 10]
t10_r2 --> [200, "TiKV", "KV Engine", 20]
t10_r3 --> [300, "PD", "Manager", 30]
```

KV mapping relationships for primary keys
```
t10_i1_100 --> 1
t10_i1_200 --> 2
t10_i1_300 --> 3
```


KV mapping relationships for secondary indexes
```
t10_i2_10_1 --> null
t10_i2_20_2 --> null
t10_i2_30_3 --> null
```