Which technique is commonly used in database systems to handle "phantom reads"?Using shared locks for all read operations.Applying range locks to cover the search criteria.Escalating row-level locks to table-level locks.Implementing timestamp-based version control

The technique commonly used in database systems to handle "phantom reads" is applying range locks to cover the search criteria.

Here's a step-by-step explanation:

1. Phantom reads occur when a transaction re-executes a query returning a set of rows that satisfy a search condition and finds that the set of rows satisfying the condition has changed due to another recently-committed transaction.

2. To prevent this, we can use a technique called range locking.

3. Range locking is a locking method that locks an index range of a table, preventing other transactions from inserting a new row in the range.

4. When a transaction performs a read operation, the database system applies a range lock to the data set, which satisfies the search criteria.

5. This lock will prevent other transactions from adding (or in some cases, modifying or deleting) rows to the data set that would satisfy the search condition.

6. Therefore, if the same read operation is performed again in the transaction, it will return the same set of rows, preventing phantom reads.

The other techniques mentioned like using shared locks for all read operations, escalating row-level locks to table-level locks, or implementing timestamp-based version control are also used in concurrency control in databases, but they are not specifically targeted at handling phantom reads.