A distributed database management system (DDBMS) would support and maintain its distributed databases.

A fixed amount of time, which is also called the access delay, is required for every message being sent from one computer to another.

The formula to compute message transmission time is as follows: Communication_time = access_delay * (data_volume / transmission_rate)

A homogeneous DDBMS is one that does not have the same local DBMS at each site.

Most DDBMSs share several important characteristics as follows: a) Location transparency, b) Replication transparency, and c) Fragmentation transparency

A DDBMS should allow a user access data at a remote site just as easily as the user accesses data from a local site.

Location transparency is the characteristic of a DDBMS that users do not need to be aware of the location of data in a distributed database.

A heterogeneous DDBMS is one that has the same local DBMS at each site.

Replication transparency means that users are very much aware of the steps taken by the DDBMS to update various copies of data.

In a heterogeneous DDBMS, at least two sites at which the local DBMSs are different.

Distributed databases (or DDBMSs) may simplify the query processing.

In a two-tier architecture, a thin client would perform the business functions, and a fat client would not perform any business functions.

In a three-tier architecture, clients perform presentation functions, database server performs database functions, and application servers perform the business functions.

URL stands for _____________ Resource Locator. ( hint: U________m )

Data replication will not create update problems that can lead to data inconsistencies.

In a DDBMS, a remote site is a site other than the one at which the user is located, and a local site is a site at which the user is located.

Fragmentation transparency means that users should be unaware of any data fragmentation in the DDBMS.

Distributed databases do not allow local control of data.

Distributed databases may make the update of replicated data more complex.

Data replication allows users at different sites to use and update copies of a database, and then share their updates with other users.

Distributed databases or DDBMSs may make the management of data dictionary much simpler and easier.

Distributed databases may increase database capability.

Data mining is to uncover new knowledge, patterns, trends, and rules from data stored in a data warehouse.

Three-tier client/server architecture is that clients perform presentation functions, database servers perform database functions, and application servers perform business functions.

Two-tier client/server architecture is that DBMS runs on file server and server sends only the requested data to the clients.

OLTP stands for Online _____________ Processing. ( hint: T______on )

The DBA of the DDBMS should correctly run and handle the updating process of replicated data.

Data dictionary is a subject-oriented, integrated, time-variant, nonvolatile collection of data in support of management’s decision-making process.

HTML stands for Hypertext _____________ Language. (hint: M________p )

Compared to file server systems, a client/server system has the advantages of decreased scalability and increased costs.

Data fragmentation means a DDBMS can divide and manage a logical object among various locations under its control.

In a two-tier architecture, server performs presentation functions, and clients perform database functions.

In general, a DDBMS does not support "fragmentation transparency" because data fragmentation would degrade the system performance.

The main purpose of data fragmentation is to place data at the location where the data is least often accessed.

Distributed databases will NOT increase system availability.

  

Distributed databases (or DDBMSs) may make the handling of concurrent update more complex due to the possibilities of local deadlock as well as global deadlock.

Fragmentation transparency means that users should be aware of the locations of their data fragments in the DDBMS.

Distributed databases may improve DDBMS performance.

Normally, a company may appoint at least one DBA to manage the DBMS, and to perform all database administration tasks.

DBA will tune a database design to improve its performance that includes creating and deleting indexes, splitting tables, and de-normalizing tables.