Page 62 - DLIS408_INFORMATION_TECHNOLOGY-APPLICATIONSL SCIENCES

Unit 5: Types of Database

crawlers and other software provide the equivalent of database indexes to support search and Notes
other activities.

In-memory Database
An in-memory database (IMDB; also main memory database or MMDB) is a database that primarily
resides in main memory, but typically backed-up by non-volatile computer data storage.
Accessing data in memory reduces the I/O reading activity and response time is critical, such as
telecommunications network equipment, main memory databases are often used.

Did u know? Main memory databases are faster than disk databases.

Operational Database

These databases store detailed data about the operations of an organization. They are typically
organized by subject matter, process relatively high volumes of updates using transactions.
Essentially every major organization on the earth uses such databases. Examples include customer
databases that record contact, credit, and demographic information about a business’ customers,
personnel databases that hold information such as salary, benefits, skills data about employees,
Enterprise resource planning that record details about product components, parts inventory, and
financial databases that keep track of the organization’s money, accounting and financial dealings.

Major Database Usage Requirements

The major purpose of a database is to provide an information system (in its broadest sense) that
utilizes it with the information the system needs according to its own requirements. A certain broad
set of requirements refines this general goal. These requirements translate to requirements for the
software tool that supports a certain database type, i.e., a DBMS, to allow conveniently building a
database of that DBMS’s type for a given application. If this goal is met by a DBMS, the designers and
builders of a specific database can concentrate on the application, and not deal with building and
maintaining the underlying DBMS. Also, since a DBMS is complex and expensive to build and
maintain, it is not economical to build such a new tool (DBMS) for every application. It is desired to
provide a flexible tool for handling databases for as many as possible given applications. A flexible,
general purpose DBMS indeed meets requirements of many information systems. However, in
some case a certain application’s database’s specific requirements cannot be met by an existing
DBMS, building a database for it (and its supporting DBMS) becomes a very complex task.

Task Define the major purposes of database.

Functional Requirements
Certain general functional requirements need to be met in conjunction with a database. They
describe what is needed to be defined in a database that supports any specific application.

Defining the Structure of Data: Data Modeling and Data Definition
Languages
The database type needs to be based on data models that are sufficiently rich to describe all the
application’s aspects needed to be supported by that database. Data definition languages exist to
describe needed databases within the models. Data definition languages are typically data model
specific.

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