Quiz # 2 | Comp 3 | Mkm 2-5

Explanation
Physical independence refers to the ability to make changes in the physical schema of a database without requiring changes in the logical schema. This means that modifications such as adding or removing columns, changing data types, or rearranging the storage structure can be made without affecting the way data is accessed or manipulated at a logical level. Physical independence allows for flexibility and scalability in database design, as it enables modifications to be made at the physical level without disrupting the logical structure and functionality of the database.

Explanation
The functions of a Database Administrator include defining the schema, which refers to the overall structure and organization of the database, including tables, relationships, and constraints. They also define the architecture of the three levels of data abstraction, which are the conceptual, logical, and physical levels. This involves designing and implementing a database system that is efficient and meets the needs of the organization. The DBA is responsible for modifying the schema as needed, such as adding or removing tables or columns. They also define the storage structure and access methods for the data, determining how it is stored and accessed, whether it is sequential, indexed, or direct. Additionally, the DBA creates user accounts, passwords, and access permissions to ensure proper security and control over the database.

Explanation
The term "DBA" stands for Database Administrator. A Database Administrator is responsible for managing and maintaining the organization's database systems. They handle tasks such as designing, implementing, and optimizing databases, ensuring data security, troubleshooting issues, and performing regular backups and updates. Therefore, the correct answer is "Database Administrator."

Explanation
Logical data independence refers to the ability to make changes in the logical schema without requiring changes in the external schema. In other words, it means that modifications to the way data is organized and structured internally do not affect the way data is accessed and used by applications or users. This allows for flexibility and ease of maintenance in database systems, as changes can be made to the logical structure without disrupting the external view of the data.

Explanation
Logical data independence refers to the ability to make changes to the logical structure of the database without affecting the applications that use it. This includes modifying the schema, adding or deleting tables, or changing relationships between tables. The other options listed, such as reduction of redundancy, sharing of data, and data integrity, are all important aspects of database management and are typically included in discussions of database design and administration. Therefore, logical data independence is the only option that is not included in the given list.

Explanation
Redundancy is not included in the given options. Physical independence refers to the ability of a system or component to function without relying on other physical components. Logical independence refers to the ability of a system or component to function without relying on other logical components. However, redundancy refers to the inclusion of extra components or systems to ensure reliability and availability in case of failure. Since redundancy is not mentioned in the options, it is the correct answer.

Explanation
The statement "There are no disadvantages in using DBMS" is false. DBMS (Database Management System) has several potential disadvantages. It can be expensive to implement and maintain, especially for large organizations. It may require specialized training and expertise to operate effectively. Additionally, DBMS can introduce a single point of failure, where a system failure or data corruption can impact the entire database. It can also have performance issues when dealing with large amounts of data or complex queries. Therefore, it is incorrect to claim that there are no disadvantages in using DBMS.

Explanation
Creating a backup and recovery policy is essential in order to protect data and ensure its availability in case of any unforeseen events such as hardware failure, natural disasters, or cyber attacks. Without a backup and recovery policy, there is a high risk of data loss and potential disruption to business operations. Therefore, the correct answer is False, as creating a backup and recovery policy is indeed essential.

Explanation
Reduction of redundancy is a significant advantage of using a DBMS because it eliminates the need for storing duplicate data. In a DBMS, data is stored in a centralized database, and multiple users can access and manipulate it simultaneously. This ensures that there is only one copy of each data item, reducing the chances of inconsistencies and data errors. By eliminating redundancy, the storage space required is minimized, and data consistency is improved. Additionally, it simplifies data maintenance and updates as changes only need to be made in one place, leading to increased efficiency and accuracy.

Explanation
Integrity constraints are rules or conditions that are defined on a database schema to ensure the accuracy, consistency, and reliability of the data. By specifying integrity constraints, such as primary key constraints, unique constraints, foreign key constraints, and check constraints, we can enforce data integrity in the database. These constraints prevent the insertion, deletion, or modification of data that would violate the defined rules. Therefore, the statement "We can maintain data integrity by specifying integrity constraints" is true.