What are the four levels of locks in order?

The correct sequence of lock levels in Teradata starts with Database, followed by Table/View, then Partition, and finally Row Hash. This hierarchy reflects the way Teradata manages concurrency and data integrity across different granularities.

At the Database level, locks are applied to the entire logical unit that consists of all objects within that database. This is the broadest level of control and ensures that access to the database as a whole is managed.

The next level, Table/View, allows for more refined locking that pertains specifically to the objects within the database. By locking at this level, Teradata provides a layer of concurrency control that allows multiple users to access different tables or views within the same database without conflicting with each other's transactions.

Following this, the Partition level is relevant for databases that use partitioning. Locking at the partition level means that operations can occur independently on different partitions of a table, thus enhancing performance and concurrency.

Lastly, Row Hash locking applies to individual rows within a table, which provides the most granular level of lock control. This allows transactions to target specific rows, reducing the likelihood of conflicts and maintaining high levels of throughput in transaction processing.

Understanding this order is critical for managing data effectively in a Teradata environment as it affects how the system optim