Data := Collection of raw bytes, items, or random information, data itself has no significant importance untill and unless we portray itself to be one.
for eg := Image can be defined as collection of pixel(raw data)
Let's consider a sample table:-
| BMI | Weight(kilos) | Height(inches) |
| 21.16 | 64 | 61 |
| 21.79 | 66 | 62 |
| 28.29 | 75 | 73 |
As Soon as we look into the table we can say that its a BMI table which has weight and height of 3 individual persons lets say 64 what does 64 itslef signifies 64$ 64pounds 64kilos 64cm it individually has no significance now as all this raw data were portrayed in a usefull and meaningfull manner it gave the table a significance
Data can be hence defined as, Raw entity which makes no sense until and unless They are grouped or put together in a meaningful state to form informations
Why is Data so Important ?
Data plays very important role be it software engineering or any buisness which use or not uses computer they need to take weekly, monthly, or annual readings and do analytics to perform the research to know how can one improve in buisness and how much effort he/she must put in a proper managed way such that they receive maximum outcomes irrespective of all the drawbacks hence its necessary to store the data for future usefull insights
What is Database ?
A database is an organized collection of data stroed electronically, designed to efficiently manage, retrieve, and update information. It allows users and applications to interact with data in a structured way, ensuring consistency and security. Databases are essential for handling large volumes of data in various fields, from business operations to software development
Advantages of Databases
1 := Data redundancy and consistency
2 := Ease in accessing of data
3 := Data Isolation
4 := Data Integration
5 := Atomicity
6 := Concurrent Accessing
7 := Security
Overview
Three Schema Architecture (view of data)
1) Physical Level / Internal Level
2) Logical Level / Conceptual Level
3) View Level / External Level
1)Physical Level / Internal Level
This level defines how the data is stored in the database. It deals with the physical storage of the data on the hardware, includind details like file organization, indexing, data compression, and encryption
This internal schema focuses on optimizing the storage and retrieval of data. It is concerned with data structures, file systems, and access methods that are efficient for that database's operations
User:= DBAs (Database Adminstrators) are typically concerned with the internal schema
2) Conceptual Schema / Logical Schema
This Level defines the structure of the entire database for a community of users. It describes what data is stored in the database and the realtionships among those data
Purpose: The conceptual Schema provides a high-level view of the database, abstracting away the complexities of the physical storage and providing a consistent representation of the data
User := Database designers and developers work at this level to define the database's structure using entities, attributes and relationships. This Schema is independent of the physical storage and the applications that access the data
3) External Schema (View Level)
This level defines how the data is viewed by individual users or applications. Different users or applications may have different views of the database depending on their needs.
The external schema provides a personalized interface for users to interact with the database. It ensures that users see only the data relevant to them, and can also hide some data or simplify the complexity of the underlying data.
User := End-users and application programs interact with the database through the external schema. Each user might have a customized view of the database.
