In database terminology, what is a distributed database and how is it organized across multiple sites?

Introduction / Context:
Modern organizations often operate in multiple locations, such as different branches, countries, or cloud regions. To support these distributed operations, databases may also be distributed across several physical sites while still appearing as a single logical database to applications and users. This question checks your understanding of the concept of a distributed database in database management systems, including the idea that data is stored on multiple computers connected by a network but managed in a coordinated way.

Given Data / Assumptions:

• We are talking about database systems, not simple file sharing.
• Multiple computers or sites are connected through a communication network.
• Users should be able to access data as if it is part of one logical database.
• Local autonomy and transparency of distribution are important characteristics.

Concept / Approach:
A distributed database is defined as a collection of logically interrelated databases distributed over a computer network. In other words, the data is physically stored on different nodes or sites, but the system is managed by a distributed database management system that provides users with transparency. Transparency means users do not need to know on which physical machine a particular piece of data resides. The distributed system handles data distribution, replication, transaction management, and concurrency control. It aims to balance data locality for performance with consistency and reliability across the networked sites.

Step-by-Step Solution:
Step 1: Identify the key idea in the term distributed database, which involves data spread across multiple sites. Step 2: Confirm that these sites are interconnected through a network so that they can communicate and coordinate. Step 3: Recognize that from the users point of view the database should still look like a single logical entity. Step 4: Compare the options and select the one that explicitly describes one logical database whose data is stored across multiple interconnected computers or locations. Step 5: Eliminate options that describe central mainframes, offline databases, email file sharing, or backup archives, because they do not match the formal definition.

Verification / Alternative check:
You can verify the definition by recalling that many textbooks define a distributed database as a set of logically related databases distributed over a network. Real world examples include distributed relational databases, NoSQL clusters, and cloud based multi region deployments. These systems all share the properties of distribution across sites and logical unity. If a system uses multiple servers but stores all data on only one of them, it is not a distributed database in the strict sense.

Why Other Options Are Wrong:
Option B is wrong because it describes a centralized database that resides on a single mainframe. Option C is incorrect because a collection of text files shared by email is not a managed database system with schema, queries, and transactions. Option D is clearly wrong, since distributed systems rely on networks and cannot require the network to be offline. Option E is misleading, because backup tapes stored off site are for disaster recovery, not an actively managed distributed database.

Common Pitfalls:
Students sometimes confuse distributed databases with simple data replication or backup strategies. Another misunderstanding is to assume that any multi tier application automatically uses distributed databases, when in fact many systems still rely on a single database server. It is also common to think distribution always means duplication, but in reality data can be partitioned or replicated depending on design. Remember that the key is a single logical database whose data is physically spread across multiple networked sites and managed by a distributed DBMS.

Final Answer:
A distributed database is best described as a single logical database whose data is stored across multiple interconnected computers or sites and managed in a coordinated way.