2. DATA
ā¢ Data is a raw, unanalyzed, unorganized, unrelated, and an uninterrupted entity
ā¢ It is derived from the Latin word āDatumā which means āsomething givenā.
ā¢ There are multiple forms of data such as numbers, letters, set of characters,
images and graphics
ā¢ Examples: weights, prices, costs, numbers of items sold,
employee names, etc.
4. INFORMATION
Information is a set of data that is processed in a
meaningful way according to the given requirement.
Example: The studentās average grade for each class,
Survey Reports and Results, Census Report, etc.
6. EXAMPLE 2
ā¢ RED
ā¢ What information we attached to the the red color is information
ā¢ For example:
ā¢ On traffic light it means stop
ā¢ In certain places the red color may mean danger zone
8. IDENTIFY IF ITS DATA OR INFORMATION
ā¢An email
OPTION A= DATA
OPTION B = INFORMATION
9. IDENTIFY IF ITS DATA OR INFORMATION
ā¢BANK STATEMENT
OPTION A= DATA
OPTION B = INFORMATION
10. IDENTIFY IF ITS DATA OR INFORMATION
ā¢YES, NO, YES, NO, NO, YES
OPTION A= DATA
OPTION B = INFORMATION
11. DATA DICTIONARY
ā¢ The data dictionary contains information of the data stored in the database and is
consulted
by the DBMS before any manipulation operation on the database. It is an integral part of
the database management systems and store meta data
12. METADATA
.
describes the database structure, sizes of data types constraints, applications,
autorization etc., that are used as an integral tool for information resource management
13. DATABASE
ā¢ A database is a collection of information that is organized so that it can be easily accessed,
managed and updated. Data is organized into rows, columns and tables, and it is indexed to
make it easier to find relevant information. Data gets updated, expanded and deleted as new
information is added
ā¢ Fields - It is the smallest unit of the data that has meaning to its users and is also called data
item or data element. Name, Address and Telephone number are examples of fields
ā¢
ā¢ Records - a collection of logically related fields and each field is possessing a fixed number
of bytes and is of fixed data type.
ā¢
ā¢ Files - A file is a collection of related records
ā¢
14.
15. COMPONENTS OF A DATABASE
1. Data item - It is defined as a distinct
piece of information
2. Relationships - It represents a
correspondence between various data
elements.
3. Constraints - These are the predicates
that define correct database states.
4. Schema - It describes the organization of
data and relationships within the database.
21. FILE BASE SYSTEM
ā¢ each file is independent of other file, and data in different files
can be integrated only by writing individual program for each
application.
22. DATABASE MANAGEMENT SYSTEM
ā¢ It is a software package designed to interact with end- users, other applications, store and
manage databases. A general-purpose DBMS allows the definition, creation, querying,
update, and administration of databases.
23. Advantages of Database Systems Disadvantages of Database Systems
1. Controlled redundancy
2. Data consistency
3. Program data independence
4. Sharing of data
5. Enforcement of standards
6. Improved data integrity
7. Improved security
8. Data access is efficient
9. Improved backup and recovery
facility
10.Minimal program maintenance
1. Complexity increases
2. Requirement of more disk space
3. Additional cost of hardware
4. Cost of conversion
5. Need of additional and specialized
manpower
6. Need for backup and recovery
7. Organizational conflict
8. More installation and management
cost
24. COMPONENTS OF DBMS
ā¢ Data Definition Language (DDL)
ā¢ It allows the users to define the database, specify the
data types, data structures and the constraints on the data to
be stored in the database
ā¢ Data Manipulation Language (DML) and Query
Language
DML allows users to insert, update, delete and retrieve data
from the database
ā¢ Software for Controlled Access of Database
This software provides the facility of controlled access of the
database by the users,concurrency control to allow shared
access of the database and a recovery control system to
restore the database in case of ardware or software failure.
25. DATABASE SYSTEM ENVIRONMENT
ā¢ Users- People who interact with the database:
Application Programmers.
End Users.
Data - Data Administrators
ā¢ Software- Lies between the stored data and the users:
- DBMS.
- Application Software.
- User Interface.
ā¢ Hardware- Physical device on which database resides.
e.g.: of database Computers, Disk Drives, Printers, Cables etc.
26. DBMS USERS
ā¢ End Users - use the database system through a menu-oriented application program, where
the type and range of response is always displayed on the screen
ā¢ Online Users - These type of users communicate with the database directly through an online
terminal or indirectly through an application program and user interface.
ā¢ Application Programmers - These are the professional programmers or software developers
who develop the application programs or user interfaces for the end user/naive and online
users.
ā¢ Database Administrator - a person who have complete control over database of any
enterprise. DBA is responsible for overall performance of database.
28. SCHEMA
ā¢ A schema is plan of the database that give the names of the entities and attributes and the
relationship among them.
ā¢ THREE TYPES OF SCHEMA
1.logical schema is concerned with exploiting the data structures offered by the
DBMS so that the schema becomes understandable to the computer. It is important
as programs use it to construct applications.
2.physical schema is concerned with the manner in which the conceptual database get
represented in the computer as a stored database.
3.View schema: Design of database at view level is called view schema. This generally
describes end user interaction with database systems
29.
30. SCHEMA
ā¢ Subschema
A subschema is a subset of the schema having the
same properties that a schema has. It
identifies a subset of areas, sets, records, and data
names defined in the database schema
available to user sessions. The subschema allows
the user to view only that part of the
database that is of interest to him. The subschema
defines the portion of the database as
seen by the application programs and the application
programs can have different view of data stored in
the database.
ā¢ Instances - The data in the database or a database
state.
31. THREE LEVEL ARCHITECTURE OF DATABASE SYSTEMS (DBMS)
BY ANSI/SPARC
1. external level - The usersā view of the
database. This level describes that part
of the
database that is relevant to each user.
2. conceptual level - The community view
of the database. This level describes what
data
is stored in the database and the
relationships among the data.
3. internal level The physical
representation of the database on the
computer. This level describes how the
data is stored in the database.
32.
33. DATA MODELS
A DATA MODEL IS A COLLECTION OF CONCEPTS THAT CAN BE USED TO
DESCRIBE THE STRUCTURE OF THE DATABASE INCLUDING DATA TYPES,
RELATIONSHIPS AND THE CONSTRAINTS THAT APPLY ON THE DATA
35. RECORD BASE DATA MODEL
represent data by using the record structures
36. HIERARCHICAL DATA MODEL
Hierarchical Data Model - organizes records in a tree structure i.e., hierarchy of parent and child records
relationships.
37.
38. NETWORK MODEL
Network Data Model - The ability of this model to handle many to many (N : N)
relations between its records is the main distinguishing feature from the hierarchical model. Thus, this
model permits a child record to have more than one parent.
39. RELATIONAL DATA MODEL
Relational Data Model - represented in the form of tables which is used interchangeably with the word
Relation. Each table consists of rows also knowns as tuples
40. ENTITY RELATIONSHIP MODEL (ER-MODEL)
ā¢ allows the representation of the various constraints as well as their relationships.
ā¢ The properties of these entities are their attributes in the ER diagram and their connections
are shown in the form of relationships.
41. OBJECT BASED DATA MODELS
These models are used in describing the data at the logical and user view levels.
These models allow the users to implicitly specify the constraints in the data
42. OBJECT ORIENTED MODEL
ā¢ Object oriented data model is also based on using real life scenarios. In this model, the scenarios
are represented as objects. The objects with similar functionalities are grouped together and linked
to different other objects.
ā¢ used for multimedia applications as well as data with complex relationships.
43. SEMANTIC DATA MODEL
ā¢ used to express greater interdependencies among
entities of interest. This class of data models are
influenced by the work done by artificial intelligence
researchers.
44. FUNCTIONAL DATA MODEL
The functional data model describes those aspects of a system concerned with transformation of
values-functions, mappings, constraints and functional dependencies
45. PHYSICAL DATA MODELS
These models provide the concepts that describes the details of how the data is stored
in the computer along with their record structures, access paths and ordering. Only
specialized or professional users can use these models
46. TWO TYPES OF PHYSICAL DATA MODEL
a. Unifying Model.
a. Frame Memory Model
47. CATEGORIES OF DATABASE SYSTEMS
ā¢ According to the Number of Users
ā¢ According to the Type of Use
ā¢ According to Database Site Locations
48. ACCORDING TO THE NUMBER OF
USERS
a. Single-user database systems - In a single user database system, the database reside
on a PCāon the hard disk. All the applications run on the same PC and directly access the
database.
b. Multiuser database systems - many PCās are connected through a Local Area Network (LAN)
and a file server stores a copy of the database files.
49. ACCORDING TO THE TYPE OF USE
a. Production or Transactional Database Systems ā used for management of supply chain
and for tracking production of items in factories, inventories of items in warehouses/stores
and orders for items.
b. Decision Support Database Systems - an interactive, computer-based systems that aid
users in judgement and choice activities
c. Data Warehouses - designed specifically to meet the transaction processing systems. It
can be loosely defined as any centralized data repository which can be queried for business
benefit.
50. ACCORDING TO DATABASE SITE LOCATIONS
a. Centralized database systems - consists of a single processor together with its associated data storage
devices and other peripherals. Database files resides on a personal computer (small enterprise) or on a
mainframe computer
b. Parallel database systems - used in the applications that have to query
extremely large databases or have to process an extremely large number of transactions per second
c. Distributed database systems - the data is spread across a variety of different databases
ā¢
d. Client/Server database systems - In client/server technology, there is a server which acts as a whole data
base management system and some clients or personal computers which are connected with server through a
network interface.
Editor's Notes
A data dictionary is a centralized repository of metadata.Ā Metadata is data about data.Ā
Constraints in DBMS (Database Management Systems) areĀ rules or conditions that are applied to the data within a database to ensure data integrity, consistency, and adherence to business rules. They define limitations and requirements that the data must meet, thereby preventing the entry of invalid or inconsistent data.
A data dictionary is a centralized repository of metadata.Ā Metadata is data about data.Ā
Schema ā overall design of a database/ or a complete description of a dbase
Logical ā what data is stored and what relationship exist in other data
Physical ā how data is stored
View schema -
he model that organizes elements of the data and tell how they relate to one-another and with the properties of real-world entities. The basic purpose of the data model is to make sure that the data stored in the data model is understood fully.
Defines theĀ mapping between the entities.
Describes theĀ state of each entity and the tasksĀ in the database.
In this, relationships among the data are represented by links. In this model, tree data structure is used.
In network type, the model data are represented by collection of records. In this, relationships among the data are represented by links. Graph data structures are used in this model. It permits a record to have more than one parent.For Example- Social Media sites like Facebook, Instagram etc.
An ER model is generally considered as a top down approach in data designing.
This model moves around three things-entity, attribute and relationship.Ā
Ā Design the entities, attributes, and their relationship in the real world.
-Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Also known as conceptual models.
Ā Represents real-world objects.
Ā·Ā Ā Ā Ā Ā Ā Ā Ā Ā Based on the collection of objects, attributes, and their relationship.
Ā·Ā Ā Ā Ā Ā Ā Ā Ā Ā Consider each object in the world as an objectĀ and isolate it from the other.
Ā·Ā Ā Ā Ā Ā Ā Ā Ā Ā Use inherits, encapsulation, abstraction properties.
n an Employee database we have different types of employees ā Engineer, Accountant, Manager, Clark. But all these employees belong to the Person group. The person can have different attributes like name, address, age, and phone.
All employees inherit the attributes and functionalities from Person, we can re-use those features in Employee.
Ā This feature of this model is calledĀ encapsulation.
Ā An extension of the ER model with notions of functions, encapsulation, and object identity, as well.Ā
Semantic data is data that has been structured to add meaning to the data. This is done by creating data relationships between the data entities to give truth to the data and the needed importance for data consumption. Semantic data helps with the maintenance of the data consistency relationship between the dat
Functional database models are used to support analytical applications such as financial planning and performance management.
This model is used to describe data at the lowest level i.e., to describe the behaviour of data at the disk level i.e., the way the data and data relationships are maintained while storing them on the disk
A unified data model bridges together various disparate data sourcesālike CRMs, BI tools,Ā product analyticsĀ platforms, ERPs, and othersāby consolidating them into a single data set or warehouse. This provides you withĀ unified data, enabling you to run analyses and make decisions while being cognizant of every data point.
Parallel DBMS isĀ a Database Management System that runs through multiple processors and disks. They combine two or more processors also disk storage that helps make operations and executions easier and faster