# Row to Kv Mappings

+ Mapping rules for non-clustered table KV
+ Mapping rules for clustered table KV


```
(A)
Key:   tablePrefix { TableID }_recordPrefixSep{ _Tidb_RowID }
Value: [col1, col2, col3, col4]
(B)
Key:   tablePrefix{ TableID }_recordPrefixSep{ Col1 }
Value: [col2, col3, col4]
```


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Indexes are an important method to solve fast queries in relational databases, so how do indexes map to KV storage
In the previous lesson, we talked about the KV mapping principle of Schema
The KV mapping for index Index is similar