Understanding Transaction Terminologies: Question and Answer

Ans: Beginning a transaction involves specifying that all subsequent operations occurring after the start of the transaction are assumed to be within the transaction.

Ans: Rolling back a transaction refers to undoing operations performed since the start of the transaction, thus restoring the affected data to its original state. This action is taken in the event of a failure.

Ans: Committing a transaction means making all operations that have occurred since the beginning of the transaction permanent. This action is performed in the event of a successful transaction.

Ans: A Dirty Read occurs when data that has not yet been committed is read. For instance, when transaction B is blocked by transaction A, and dirty reads are allowed, transaction B may end up reading transaction A's changes even though they have not yet been committed.

Ans: Nonrepeatable Read refers to a situation in which transaction B modifies the data that transaction A was working with during transaction A's lifetime. Consequently, transaction A reads modified data, and the original read is no longer possible.

Ans: Phantom Read describes a scenario in which the number of rows changes between two reads within the same transaction, similar to a non-repeatable read. Phantom rows are those rows that differ between the two reads.

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