Define the following terms. i. Database ii. Database Management System iii. Data Model iv. Schema v. Data Independence
Database:
A collection of
related information stored in a structured format. Database is often used
interchangeably with the term table
(Lotus Approach, for instance, uses the term database instead of table).
Technically, they're different: A table is a single store of related
information; a database can consist of one or more tables of information that
are related in some way. For instance, you could track all the information
about the students in a school in a students table. If you then created
separate tables containing details about teachers, classes and classrooms, you
could combine all four tables into a timetabling database. Such a multi-table
database is called a relational database..
Database
Management System:
A Database
Management System is a collection of interrelated data and a set of programs to
access that data. The primary goal of a DBMS is to provide a way to store and
retrieve database information that is both convenient and efficient.
Data Model:
Data modeling is the analysis of data objects that
are used in a business or other context and the identification of the
relationships among these data objects. Data modeling is a first step in doing object-oriented
programming. As a result of data modeling, you can then define the classes
that provide the templates for program objects.
Schema:
The collection
of information stored in the database at a particular moment is called an
instance of the database. The overall design of the database is called the
database schema. Schemas are changed infrequently. Database systems have several schemas,
partitioned according to the levels of abstraction. The physical schema,
logical schema and subschema.
Data Independence:
Data
independence occurs when the structure of the database can change without
requiring programs that access the database to change. Data independence is
achieved through the use of the view. Each program accesses data through an
external view. The underlying structure of the database can change without
requiring a change in the external view. The change to the database structure
should be such that a required field should not be removed from the database
structure.