1) (True/False) In SQL you can indicate that a group of database operations form

Question

1) (True/False) In SQL you can indicate that a group of database operations form a transaction. _____________

2) (Multiple Choice) A transaction “schedule” is

a) gives the times at which operations of a transaction must occur

b) lists the order in which operations from multiple transactions must occur

c) lists the priority of transactions within a group of transactions.

3) (True/False) A transaction schedule may re-order operations within a transaction. __________

4) (True/False) If a transaction schedule is conflict serializable then it is serializable. __________

Explanation / Answer

1)

True

2)

b) lists the order in which operations from multiple transactions must occur

3)

True: We can reorder the non-conflicting operation

4)

True

Explanation:

A schedule is an abstract model to describe execution of transactions running in the system. Often it is a list of operations (actions) ordered by time, performed by a set of transactions that are executed together in the system. If order in time between certain operations is not determined by the system, then a partial order is used. Not all transaction operation types should be included in a schedule, and typically only selected operation types (e.g., data access operations) are included, as needed to reason about and describe certain phenomena. Schedules and schedule properties are fundamental concepts in database concurrency control theory.

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