Knowledge in Databases

COMPUTER DATABASE SKILLS FOR COMMERCE STUDENTS

What is DBMS? Database is a collection of related data and data is a collection of facts and figures that can be processed to produce information. Mostly data represents recordable facts. Data aids in producing information, which is based on facts. For example, if we have data about marks obtained by all students, we can then conclude about toppers and average marks. A database management system stores data in such a way that it becomes easier to retrieve, manipulate, and produce information. Characteristics Traditionally, data was organized in file formats. DBMS was a new concept then, and all the research was done to make it overcome the deficiencies in the traditional style of data management. A modern DBMS has the following characteristics − • Real-world entity − A modern DBMS is more realistic and uses real-world entities to design its architecture. It uses the behavior and attributes too. For example, a school database may use students as an entity and their age as an attribute. • Relation-based tables − DBMS allows entities and relations among them to form tables. A user can understand the architecture of a database just by looking at the table names. • Isolation of data and application − A database system is entirely different than its data. A database is an active entity, whereas data is said to be passive, on which the database works and organizes. DBMS also stores metadata, which is data about data, to ease its own process. • Less redundancy − DBMS follows the rules of normalization, which splits a relation when any of its attributes is having redundancy in values. Normalization is a mathematically rich and scientific process that reduces data redundancy. • Consistency − Consistency is a state where every relation in a database remains consistent. There exist methods and techniques, which can detect the attempt of leaving the database in an inconsistent state. A DBMS can provide greater consistency as compared to earlier forms of data storing applications like file-processing systems. • Query Language − DBMS is equipped with a query language, which makes it more efficient to retrieve and manipulate data. A user can apply as many and as different filtering options as required to retrieve a set of data. Traditionally it was not possible where the file-processing system was used. • ACID Properties − DBMS follows the concepts of Atomicity, Consistency, Isolation, and Durability (normally shortened as ACID). These concepts are applied to transactions, which manipulate data in a database. ACID properties help the database stay healthy in multi-transactional environments and in case of failure. • Multiuser and Concurrent Access − DBMS supports a multi-user environment and allows them to access and manipulate data in parallel. Though there are restrictions on transactions when users attempt to handle the same data item, but users are always unaware of them. • Multiple views − DBMS offers multiple views for different users. A user who is in the Sales department will have a different view of the database than a person working in the Production department. This feature enables the users to have a concentrated view of the database according to their requirements. • Security − Features like multiple views offer security to some extent where users are unable to access data of other users and departments. DBMS offers methods to impose constraints while entering data into the database and retrieving the same at a later stage. DBMS offers many different levels of security features, which enables multiple users to have different views with different features. For example, a user in the The sales department cannot see the data that belongs to the Purchase department. Additionally, it can also be managed how much data of the Sales department should be displayed to the user. Since a DBMS is not saved on the disk as traditional file systems, it is very hard for miscreants to break the code.

DBMS Basics

This pin covers the basic theory of traditional DBMS, Good for beginners. Three tier architecture, ER model, etc. It has Characteristics,Models, structures, schema diagram,examples, advantages of using the DBMS structure annd getting an introduction in the theory part of database management system.

DBMS(database management system)

The DBMS manages incoming data, organizes it, and provides ways for the data to be modified or extracted by users or other programs. Some DBMS examples include MySQL, PostgreSQL, Microsoft Access, SQL Server, FileMaker, Oracle, RDBMS, dBASE, Clipper, and FoxPro. Database Management System (DBMS) is a software for storing and retrieving users' data while considering appropriate security measures. It consists of a group of programs which manipulate the database.

Database chisquare testing

In this you will learn about that how to do chi square testing