Managing Multiuser Databases MCQs with Explanations

Phantom read does not refer to modifications or deletions of existing rows. It occurs when a transaction reads a set of rows that satisfy a condition, and then, upon re-execution of the same query, finds additional rows (phantoms) that were inserted by another committed transaction. This is different from non-repeatable reads , where a transaction rereads data and finds that it has been modified or deleted by another transaction. Therefore, the statement given in the question describes a non-repeatable read , not a phantom read.

explicit locks is the correct answer to “Locks placed by command are called ________ .”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Shared lock is the correct answer to “Which of the following locks the item from change but not from read”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Phantom read is the correct answer to “Which of the following occurs when a transaction rereads data and finds new rows that were inserted by a command transaction since the prior read”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

durable. is the correct answer to “A transaction for which all committed changes are permanent is called:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Read committed is the correct answer to “In this instance, dirty reads are disallowed, while nonrepeatable reads and phantom reads are allowed.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Nonrepeatable read is the correct answer to “Which of the following occurs when a transaction rereads data it has previously read and finds modification or deletions caused by a committed transaction”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

the lock is obtained only after the transaction has processed. is the correct answer to “The advantage of optimistic locking is that:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Keyset is the correct answer to “Which of the following refers to a cursor type that when the cursor is opened, a primary key value is saved for each row in the recordset; when the application accesses a row, the key is used to fetch the current values of the row”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Dynamic is the correct answer to “Which of the following refers to a cursor type where changes of any type and from any source are visible”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Repeatable read is the correct answer to “Which of the following disallows both dirty reads and nonrepeatable reads, but allows phantom reads”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Serializable is the correct answer to “Dirty read, nonrepeatable, and phantom reads are not possible in this instance.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

atomic. is the correct answer to “A transaction in which either all of the database actions occur or none of them do is called:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

forward only. is the correct answer to “A cursor type in which the application can only move forward through the recordset is called:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Dirty read is the correct answer to “Which of the following occurs when one transaction reads a changed record that has not been committed to the database”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Read uncommitted is the correct answer to “Which of the following allows dirty reads, nonrepeatable reads and phantom reads to occur”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Exclusive lock is the correct answer to “Which of the following locks the item from access of any type”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

lock granularity is the correct answer to “The size of a lock is called:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

static is the correct answer to “A cursor type in which the application sees the data as they were at the time the cursor was opened is called:”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

Both the first and third answers above are correct. is the correct answer to “What is the overall responsibility of the DBA”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

implicit locks is the correct answer to “Locks placed by the DBMS are called ________ .”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “Resource locking is a process to prevent multiple applications from obtaining copies of the same record when the record is about to be changed.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “The overall responsibility of the DBA is to facilitate the development and use of the database.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “The size of the lock is referred to as the lock granularity.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “A durable transaction is one in which all committed changes are permanent.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “An ACID transaction is one that is atomic, consistent isolated, and durable.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “When one transaction reads a changed record that has not been committed to the database a filthy read occurs.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “The size of a lock is referred to as lock sizing.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “When two transactions are being processed against the database at the same time they are termed concurrent transactions.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “Locks placed by the DBMS are explicit locks.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “In optimistic locking, the assumption is made that conflict will occur.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “Two transactions that run concurrently and generate results that are consistent with the results that would have occurred if they had run separately are referred to as serializable transactions.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “The lost update problem is when User A reads data that have been processed by a portion of a transaction from User B.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “The transaction log contains a copy of every database record (or page) after it has changed. These records are called before images.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “Database administration refers to a function that applies to the entire organization.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “Locks placed by command are implicit locks.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “The goal of database security is to ensure that only authorized users can perform authorized activities at authorized times.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

True is the correct answer to “A transaction is a series of actions to be taken on the database so that either all of them are performed successfully or none of them are performed at all.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “A point of synchronization between the database and the transaction log is generally referred to as a stop point.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.

False is the correct answer to “An exclusive lock locks the item from change but not from read.”. This question is standard in competitive examination syllabi for Managing Multiuser Databases.