Database Architecture And File Management Systems Mastery Practice Tests

Question 1

A system stores $N = 1000$ records, each with a fixed size of $S = 256$ bytes. If the disk block size is $B = 4096$ bytes, calculate the total number of blocks required to store the file, assuming no overhead.

Accepted Answer

63

Question 2

A database uses variable-length records. If the average record size is $A = 120$ bytes and the overhead per record is $O = 8$ bytes, what is the expected storage efficiency if the block size is $B = 1024$ bytes and we store $K = 8$ records per block?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 3

In a sequential file organization, the time complexity to perform a search for a specific record is $O(N)$ where $N$ is the number of records.

Accepted Answer

True

Answer

False

Question 4

Which of the following scenarios favor the use of fixed-length records over variable-length records?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 5

If an ISAM index structure has a branching factor of $f = 100$ and the file has $N = 1,000,000$ records, determine the minimum number of levels required to access any record.

Accepted Answer

3

Question 6

A file system stores records in a heap (serial) organization. If a new record of size $S = 500$ bytes is added to a file that already occupies $M = 10,000$ bytes, what is the new file size?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 7

Variable-length records are generally more efficient than fixed-length records when the data fields have highly varying lengths, such as text descriptions.

Accepted Answer

True

Answer

False

Question 8

In a file system, if $N$ users access $M$ files independently, the number of redundant data instances is often proportional to $N 	imes M$. If a DBMS reduces this to $O(M)$ by centralizing storage, calculate the reduction factor in storage complexity for a system where $N=100$ and $M=50$.

Accepted Answer

100

Answer

50

Answer

500

Answer

2500

Question 9

Consider a database system where the physical storage layout changes from a B-tree index to a Hash index. Which of the following levels of abstraction remain unaffected due to physical data independence?

Answer

Internal Level

Answer

Conceptual Level

Answer

View/External Level

Answer

Hardware Level

Question 10

If a system maintains $I$ integrity constraints, and the probability of a single constraint violation in a file system is $p$, the probability of data inconsistency in a system with $I$ constraints is $1 - (1-p)^I$. If $p=0.01$ and $I=10$, the probability of inconsistency is approximately $0.0956$.

Accepted Answer

True

Answer

False

Question 11

A database administrator modifies the conceptual schema to add a new entity relationship. If the system supports logical data independence, calculate the number of external views that must be updated if there are $V$ total views and $k$ views depend on the modified entity. The answer should be expressed as a function of $k$.

Accepted Answer

k

Question 12

Given a storage cost function $C(S) = \alpha S + \beta R$, where $S$ is total data size and $R$ is the redundancy factor. If a DBMS reduces $R$ from $0.8$ to $0.1$ while keeping $S$ constant at $1000$ units and $\alpha=1, \beta=500$, determine the total cost savings.

Accepted Answer

350

Answer

400

Answer

450

Answer

500

Question 13

Which of the following scenarios demonstrate a violation of data independence in a poorly designed system?

Answer

Changing the data type of a column in the physical table forces a rewrite of all application queries.

Answer

Adding a new table to the database requires modifying existing user views that do not even reference the new table.

Answer

Updating the physical storage index improves query performance without changing the logical schema.

Answer

Adding a new attribute to the conceptual schema only requires updating the views that utilize that specific attribute.

Question 14

In a hierarchical database model, if a parent node has $n$ children and each child has $m$ sub-children, calculate the total number of leaf nodes in a tree with a height of $h=3$ (where the root is level 1).

Accepted Answer

n 	imes m

Answer

n + m

Answer

n^m

Answer

m^n

Question 15

Given a relation $R$ with $A$ attributes and $T$ tuples, if the storage manager requires $S$ bytes per tuple and an overhead of $O$ bytes per page, calculate the total storage $B$ in bytes required for $P$ pages.

Accepted Answer

P 	imes (S 	imes \frac{T}{P} + O)

Question 16

If a query optimizer evaluates two execution plans, Plan A with cost $C_A = 100 + 0.05N$ and Plan B with cost $C_B = 200 + 0.01N$, where $N$ is the number of records, determine the threshold $N$ above which Plan B becomes more efficient.

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 17

In a DBMS architecture, the buffer manager uses a replacement policy to manage $M$ frames in memory. If the hit ratio is $H$, the average access time is calculated as $T_{avg} = H 	imes T_{mem} + (1 - H) 	imes T_{disk}$.

Accepted Answer

True

Answer

False

Question 18

Which of the following SQL command categories are correctly identified for a standard DBMS?

Answer

DDL: CREATE, ALTER, DROP

Answer

DML: SELECT, INSERT, UPDATE, DELETE

Answer

DCL: COMMIT, ROLLBACK

Answer

TCL: GRANT, REVOKE

Question 19

A transaction manager ensures atomicity. If a transaction $T_i$ performs $k$ operations, each with a failure probability $p$, calculate the probability $P_{success}$ that the entire transaction completes successfully.

Accepted Answer

(1 - p)^k

Question 20

In an Entity-Relationship model, if an entity set $E$ has $n$ attributes and a relationship $R$ connects $E$ to itself (unary), what is the minimum number of foreign keys required in the relational mapping to represent this relationship?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Database Architecture And File Management Systems Mastery Practice Tests

Practice Tests

Database Architecture and File Management Systems Mastery

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