# Primary Key and Index (Continued...)

```
CREATE TABLE `stars` (
  `id` ~!@BIGINT@!~ AUTO_RANDOM,
  `name` CHAR(20) NOT NULL DEFAULT '',
  `mass` FLOAT NOT NULL DEFAULT 0.0 COMMENT '10**24 kg',
  ...
  `distance_from_earth` FLOAT COMMENT 'light year',
  `discover_date` DATETIME DEFAULT NULL,
  ~!@PRIMARY KEY (`id`)@!~,
  KEY (`name`)
);

tidb> SELECT _tidb_rowid FROM universe.stars;
ERROR 1054 (42S22): ~!@Unknown column '_tidb_rowid'@!~ in 'field list'

tidb> SELECT tidb_row_id_sharding_info, tidb_pk_type 
    -> FROM information_schema.tables 
    -> WHERE table_name='stars';
+---------------------------+--------------+
| tidb_row_id_sharding_info | tidb_pk_type |
+---------------------------+--------------+
| PK_AUTO_RANDOM_BITS=5     | ~!@CLUSTERED@!~    |
+---------------------------+--------------+
1 row in set (0.00 sec)
```

------------------------------------------------------------

For table with INT like column as primary key, _tidb_rowid implicit column is not available.

```
tidb> CREATE TABLE test.dropme (
    ->   id BIGINT AUTO_RANDOM,
    ->   name CHAR(35) NOT NULL,
    ->   PRIMARY KEY (id)
    ->   );

tidb> select key_name, column_name, index_id from information_schema.tidb_indexes 
    ->    where table_schema='test' and table_name='dropme';
+----------+-------------+----------+
| key_name | column_name | index_id |
+----------+-------------+----------+
| PRIMARY  | id          |        0 |
+----------+-------------+----------+
```