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Database Management Systems/Managing Database
Notes 1.1 Database Management Systems (DBMS)
A database is a collection of related data stored in a standard format, designed to be shared by
multiple users. A database is defined as “A collection of interrelated data items that can be
processed by one or more application programs”.
A database can also be defined as “A collection of persistent data that is used by the application
systems of some given enterprise”. An enterprise can be a single individual (with a small
personal database), or a complete corporation or similar large body (with a large shared database),
or anything in between.
Example: A Bank, a Hospital, a University, a Manufacturing company.
Data
Data is the raw material from which useful information is derived. The word data is the plural
of Datum. Data is commonly used in both singular and plural forms. It is defined as raw facts or
observations. It takes variety of forms, including numeric data, text and voice and images. Data
is a collection of facts, which is unorganized but can be made organized into useful information.
The term Data and Information come across in our daily life and are often interchanged.
Example: Weights, prices, costs, number of items sold etc.
Information
Data that have been processed in such a way as to increase the knowledge of the person who uses
the data. The term data and information are closely related. Data are raw material resources that
are processed into finished information products. The information as data that has been processed
in such way that it can increase the knowledge of the person who uses it.
In practice, the database today may contain either data or information.
Data Processing
The process of converting the facts into meaningful information is known as data processing.
Data processing is also known as information processing.
Metadata
Data that describe the properties or characteristics of other data.
Data is only become useful when placed in some context. The primary mechanism for providing
context for data is Metadata. Metadata are data that describe the properties, or characteristics of
other data. Some of these properties include data definition, data structures and rules or
constraints. The Metadata describes the properties of data but do not include that data.
It allows the database designer and users to understand what data Exit, what the data mean, and
what the fine distinctions are between seemingly similar data items. The management of Metadata
is at least as a crucial as meaning the associated data since data without clear meaning can be
confusing, misinterpreted or erroneous.
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