Introduction To Database Management System

INTRODUCTION TO DATABASE
MANAGEMENT SYSTEM
INTRODUCTION TO DATABASE
MANAGEMENT SYSTEM
 What is introduction of DBMS?

Database management system (DBMS) is a software application that is used to
create ,access , maintain , and manage databases.
Basic Definitions and Concept
 There are three main types of DBMS data models relational , network, and
hierarchical. Relational data model Data is organized as logically independent
tables.
 RELATIONAL
 NETWORK
 HIERARCHICAL
META DATA a meta data is the data about the data. It is the self-describing nature
of databases. It holds the information about each data element in the databases. Such
as names , types, range of values, access authorization, indicate which application
program uses the data.
DATA DICTIONARY is a collection of names, definitions, and attributes about
data elements that are being used or captured in a database, information system, or
part of a research project.
DATABASE a database is an organized collection of structured information, or
data, typically stored electronically in a computer system. A database is usually
controlled by a Database Management System (DBMS).
 COMPONENTS OF DATABASE the five major components of a database
are hardware, software , data , procedure , and database access language
 DATABASE MANAGEMENT SYSTEM are a software system used to
store, retrieve, and run queries on data. A DBMS serves as an interface between
an end-user and a database, allowing users to create, read , update and delete in
the database.
TRADITIONAL FILE SYSTEM VERSUS DATABASE SYSTEM
 DISADVANTAGES OF TRADITIONAL FILE SYSTEM

- Data redundancy and inconsistency
- Difficulty in accessing data.
- Data isolation – multiple files and formats
- Integrity problems.
- Unauthorized access is not restricted
- It co-ordinates only physical access
 Database system or database system environment is a
collective system of components that comprise and regulates group of data,
management, and use of data, which consist of software, hardware, people,
techniques, of handling database, and the data also.
 Advantage of database system Improve data sharing and security ,
Effective data integration , Consistent reliable data , Data that complies with
privacy regulations , Increased productivity , Better decision making.
 Disadvantage of database system More costly creating and
managing a database is quite costly , High complexity , Database failure , High
hardware cost, Huge size, Upgradation cost , Cost of data conversion.
DBMS USERS
 END USERS OR NAIVE USER Database Administrator , Naive /

Parametric end users , System analyst , Sophisticated Users , Database designers,
Application program , Casual / Temporary users
 ONLINE USERS Online users may communicate with database directly

through an online terminal or directly through user interface and application
programs. Sophisticated users – They are those users who interact with the system
without writing the program instead they form their request in database query
language.
 APPLICATION PROGRAMMERS The Application Programmer's role is to assist
in the definition, development, testing, analysis, and maintenance of new or existing
software applications in support of the achievement of business requirements. This
includes writing, coding, testing, and analyzing software programs and applications.
 DATA BASE ADMINISTRATOR A Database Administrator (DBA) is individual
or person responsible for controlling, maintenance, coordinating, and operation of
database management system. Managing, securing, and taking care of database system
is prime responsibility.
DATABASE OR DBMS LANGUAGE
 DATA DEFINITION LANGUAGE Data Definition Language (DDL) is used to

create and modify the structure of objects in a database using predefined commands
and a specific syntax. These database objects include tables, sequences, locations,
aliases, schemas and indexes.
 STORAGE DEFINITION LANGUAGE SDL stands for Storage Definition
Language. SDL matter is almost anything that's not specified by SQL standard. It is
different in every DBMS which specifies anything to do with how or where data in
relevant table is stored.
 VIEW DEFINITION LANGUAGE View Definition Language (VDL): This
language is used to specify user views and their mapping to conceptual schema. It
defines the subset of records available to classes of users.
 DATA MANIPULATION LANGUAGE Data Manipulation Language or DML is a
subset of operations used to insert, delete, and update data in a database. A DML is
often a sublanguage of a more extensive language like SQL; DML comprises some of the
operators in the language.
 FOURTH GENERATION LANGUAGE The fourth-generation languages, or 4GL,
are languages that consist of statements similar to statements in a human language.
Fourth generation languages are commonly used in database programming and scripts
examples include Perl, PHP, Python, Ruby, and SQL
SCHEMAS, SUBSCHEMA AND INSTANCES
 SCHEMA In psychology and cognitive science, a schema describes a pattern of

thought or behavior that organizes categories of information and the relationships among
them.
 SUBSCHEMA Subschema. A subschema provides a view of the database as seen by
an application program. This view is often a subset of the complete schema definition.
 INSTANCES The data stored in database at a particular moment of time is called
instance of database. Database schema defines the variable declarations in tables that
belong to a particular database; the value of these variables at a moment of time is called
the instance of that database.
THREE LEVEL ARCHITECTURE OF DATABASE SYSEM
• LEVELS OR VIEWS
• LEVELS Physical Level. This is the lowest level in the three level
architecture. ...
• Conceptual Level. The conceptual level is at a higher level than the physical
level. ...
• External Level. This is the highest level in the three level architecture and closest
to the user.
• VIEWS
• There are two types of database views dynamic views and static views.
 DIFFERENT MAPPINGS IN THREE LEVEL ARCHITECTURE
OF DMS External level , Conceptual level , Internal level
 Advantages of three-level architecture The key three-tier benefit
is improved scalability, since the application servers can be deployed on many
machines. · It improves data integrity.
 DATA INDEPENDENCE Data independence is the ability to modify one
level of a DBMS without affecting the next higher level's data structure or
access methods. It's of two types, physical and logical.
DATA MODELS
 TYPES OF DATA MODELS Conceptual Data Model , Logical Data Model, Physical Data Model
 COMPARISON OF VARIOUS DATA MODELS
 POPERTY Data element organization , Identy , Data Independence , Relationship Organization
 HIERARCHICAL File records , Record based , Logical Proximity in a linearized tree.
 NETWORK Files records , Record based , Intersecting Networks
 RELATIONAL Tables/tuples , Value based , Indentifiers of rows in one table are embedded as
attribute values in another table.
 E-R DIAGRAM Objects entity sets , Value base , Relational extenders that support specialized
applications.
 OBJECT – ORIENTED Objects , Record based , Logical containment , Procedural
 WHICH DATA MODELS TO USE From the available record based data models,
the relational data model is most commonly used model by most of the organizations
because of the following reasons:
 It provides very powerful search, selection and maintenance of
data.
 It provides ad hoc query capability
TYPES OF DATABASE SYSTEM
 Single-user database systems : In a single user database system, the

database reside on a PC–on the hard disk. All the applications run on the same
PC and directly access the database.
 Multiuser database systems : In a multiuser database system, many
PC’s are connected through a Local Area Network (LAN) and a file server stores
a copy of the database files. Each PC on the LAN is given a volume name on the
file server.
 According to the Number of Users According to the number of
users, the database systems can be further subdivided into two categories,
namely:
 (a) Single-user database systems
 (b) Multiuser database systems
 According to the Type of Use According to the type of use, the database
systems can be further subdivided into three categories, namely:
 (a) Production or Transactional Database Systems
 (b) Decision Support Database Systems
 (c) Data Warehouses.
 According to Database Site Locations According to database site
locations, database systems can be further subdivided into four categories
namely:
 (a) Centralized database systems
 (b) Parallel database systems
 (c) Distributed database systems
 (d) Client/Server database systems.

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INTRODUCTION TO DATABASE

 What is introduction of DBMS?

 DISADVANTAGES OF TRADITIONAL FILE SYSTEM

 END USERS OR NAIVE USER Database Administrator , Naive /

 ONLINE USERS Online users may communicate with database directly

 DATA DEFINITION LANGUAGE Data Definition Language (DDL) is used to

 SCHEMA In psychology and cognitive science, a schema describes a pattern of

 Single-user database systems : In a single user database system, the

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