Recovery System: Data Recovery

This set of MCQs helps students to learn about Database recovery which is the process of restoring the database to a correct (consistent) state in the event of a failure, Recovery restores a database form a given state, usually inconsistent, to a previously consistent state.

Start Quiz

The log is a sequence of _________ recording all the update activities in the database.

Log records Records Entries Redo

In the ___________ scheme, a transaction that wants to update the database first creates a complete copy of the database.

Shadow copy Shadow Paging Update log records All of the mentioned

The ____________ scheme uses a page table containing pointers to all pages; the page table itself and all updated pages are copied to a new location.

Shadow copy Shadow Paging Update log records All of the mentioned

The current copy of the database is identified by a pointer, called ____________ which is stored on disk.

Db-pointer Update log Update log records All of the mentioned

If a transaction does not modify the database until it has committed, it is said to use the ___________ technique.

Deferred-modification Late-modification Immediate-modification Undo

If database modifications occur while the transaction is still active, the transaction is said to use the ___________technique.

Deferred-modification Late-modification Immediate-modification Undo

____________ using a log record sets the data item specified in the log record to the old value.

Deferred-modification Late-modification Immediate-modification Undo

In the __________ phase, the system replays updates of all transactions by scanning the log forward from the last checkpoint.

Repeating Redo Replay Undo

The actions which are played in the order while recording it is called ______________ history.

Repeating Redo Replay Undo

If attributes A and B determine attribute C, then it is also true that:

A → C. B → C. (A,B) is a composite determinant. C is a determinant.

If attribute A determines both attributes B and C, then it is also true that:

A → B. B → A. C → A. (B,C) → A.

In a relation, the order of the rows matters.

True False

A special redo-only log record < Ti, Xj, V1> is written to the log, where V1 is the value being restored to data item Xj during the rollback. These log records are sometimes called,

Log records

Records

Compensation log records

Compensation redo records

A tuple is a(n):

Column of a table.

Two dimensional table.

Row of a table.

Key of a table.

One solution to the multivalued dependency constraint problem is to:

Split the relation into two relations, each with a single theme.

Change the theme.