Question at position 45 If the transaction is completely isolated, only deleting rows is allowed.TrueFalse单项选择题
A
True
B
False

Question

Question at position 45 If the transaction is completely isolated, only deleting rows is allowed.TrueFalse

BlackTom AI · Accepted Answer

Question at position 45: If the transaction is completely isolated, only deleting rows is allowed.TrueFalse

Option 1: 'True' — This statement asserts that a completely isolated transaction permits only deletions within the transaction. In standard transactional databases, isolation level determines visibility and effects of concurrent transactions, but it does not inherently restrict the types of DML (Data Manipulation Language) operations to only deletions. A fully isolated (high isolation) transaction can still perform inserts, updates, and deletes as needed; restricting to deletions would be an artificial limitation and is not a general rule of isolation semantics.

Option 2: 'False' — This option correctly challenges the blanket claim in Option 1. Even under strict isolation, a transaction can typically perform a variety of operations beyond deletions, such as inserting new rows, updating existing ones, and deleting rows. The isolation level affects how and when changes become visible to other transactions and how anomalies are prevented, not a prohibition on the kinds of DML statements executed within the transaction.

Extra nuance: The concept of isolation often refers to phenomena like dirty reads, non-repeatable reads, and phantom reads, and levels such as read uncommitted, read committed, repeatable read, and serializable. None of these levels inherently restrict DML statements to only deletions; the statement in Option 1 conflates isolation with a narrow operation scope, which misrepresents how transactions behave. Therefore, the claim in Option 1 is incorrect, and Option 2 correctly identifies the situation as false.

Question at position 45 If the transaction is completely isolated, only deleting rows is allowed.TrueFalse单项选择题

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