DBMS Miscellaneous : MCQs & PYQs with Explanation

Option A

RAID (Redundant Array of Independent Disks) is a storage technology that combines multiple physical disks into a single logical unit to improve performance and reliability (fault tolerance). Key characteristics of RAID include:

• Data Striping: Distributing data across multiple disks to improve read/write performance.
• Redundancy/Parity: Using extra disk space to store parity or mirrored data for fault tolerance.
• Logical View: The OS treats the RAID array as a single logical drive, even though it consists of multiple physical drives.

Option B

A Work File is a temporary file created by an information system to perform a specific or single task. It is used to hold intermediate data during processing and is usually discarded after the task is completed.

Option A

RAID (Redundant Array of Independent Disks) is used to improve data reliability and performance. Different RAID levels use different techniques like mirroring and parity.

• Parity is a method used to recover data if a disk fails.
• Some RAID levels use parity, while others do not.

The RAID 1 uses mirroring, not parity. Data is duplicated on two or more disks. If one disk fails, the same data is available on the other disk.

Option A

A Flow Chart is a graphical technique that can be used to organize and present information in a logical sequence. It uses standard symbols and arrows to show the flow or relationship between different steps or pieces of information.
Transition devices, on the other hand, are words or phrases used mainly to connect sentences, paragraphs, or ideas and make written communication smooth and coherent. Examples include however, therefore, furthermore, first, next, and finally. They are not considered a method for organizing notes.

Option A

QBE (Query By Example) is a graphical query language where users specify queries by filling example values in tables. The condition box in QBE is specifically used to define constraints or conditions on domain variables, such as comparisons, ranges, or logical conditions.

• The SQL uses the WHERE clause, not a condition box.

Option A

The DUAL table is a special one-row, one-column table provided by Oracle. It is commonly used to evaluate expressions, call functions, or display system values without referencing any user table. 
The owner of the DUAL table is SYS, which is the default system schema in Oracle.

Option C

According to the Bell-LaPadula security model, a subject S is permitted to write to an object O only if the security classification of the subject satisfies the condition:
class(S)≤class(O)
This is known as the "No Write Down" or Star (*) Property rule, which prevents a subject from writing information to a lower security level object, thereby preventing potential information leakage from higher classified data to lower classification levels.

Option C

A fourth-generation language (4GL) is a non-procedural language that allows users to specify what result is required, not how to compute it.
SQL fits this definition because users write queries to describe the desired data, and the DBMS decides the execution steps.

Option D

Database security is maintained using:

• Data Encryption protects data from unauthorized access by converting it into unreadable form.
• Passwords authenticate users before allowing access to the database.
• Granting Privileges controls what actions a user can perform.

Option A

Knowledge Management (KM) is the systematic process of identifying, collecting, organizing, storing, sharing, and disseminating knowledge and information within an organization. 
Its main purpose is to ensure that useful knowledge is available to the right people at the right time, so they can make better decisions and perform their work effectively.
The important activities of Knowledge Management include, Identify → Organize → Store → Share → Disseminate → Use Knowledge.