Important Properties of databases:
It means that data reside on stable storage such as a magnetic disk.
Persistency depends on
relevance of intended usage.
Organizations need to retain data about Customers Record, Suppliers and
Inventory on stable storage because these data are repetitively used.
It means that a database can have multiple uses and users.
A database provides a common
memory or multiple functions in an organization.
Many users can use a database at the same time.
A personnel database can support payroll calculations, performance evaluation,
government reporting requirements, etc.
It means that data stored as separate units can be connected to provide a whole picture.
is a cluster of data usually about one topic that can be accessed together.
A customer database relates customer data (name, address, ….etc) to order data (order
number, order date,…) to facilitate order processing.
Features of Database Management Systems
DBMS contains information about a particular enterprise
Collection of interrelated data
Set of programs to access the data
An environment that is both
Banking: all transactions
Airlines: reservations, schedules
Sales: customers, products, purchases
Online retailers: order tracking, customized recommendations
Manufacturing: production, inventory, orders, supply chain
employee records, salaries, tax deductions
Databases touch all aspects of our lives
A Database Management System (DBMS), is a collection of software that supports the creation,
use and maintenance of databases.
Initially, DBMS provided efficient storage and retrieval of data.
DBMS have evolved to provide a broad range of features for data acquisition, storage, and dissemination,
maintenance, retrieval, and formatting.
language and graphical tools to define entities, relationships, integrity
constraints, and authorization rights.
– Language and graphical tools to access data without complicated
– Graphical tools to develop menus, forms, and reports.
Procedural Language Interface
– Language that combines nonprocedural access with full
capabilities of a programming language.
– Control mechanisms to prevent interference from simultaneous users
and recover lost data after a failure.