Data base introduction
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What is Data?
Data is nothing but facts and statistics stored or free flowing over a network, generally it ‘ s raw and unprocessed. For example: When you visit any website, they might store you IP address, that is data, in return they might add a cookie in your browser, marking you that you visited the website, that is data, your name, it ‘ s data, your age, it ‘ s data.
Data becomes information when it is processed, turning it into something meaningful. Like, based on the cookie data saved on user ‘ s browser, if a website can analyse that generally men of age 20 – 25 visit us more, that is information, derived from the data collected.
What is a Database?
A Database is a collection of related data organised in a way that data can be easily accessed, managed and updated. Database can be software based or hardware based, with one sole purpose, storing data.
During early computer days, data was collected and stored on tapes, which were mostly write – only, which means once data is stored on it, it can never be read again. They were slow and bulky, and soon computer scientists realised that they needed a better solution to this problem.
Larry Ellison, the co – founder of Oracle was amongst the first few, who realised the need for a software based Database Management System.
What is DBMS?Page – 2
A DBMS is a software that allows creation, definition and manipulation of database, allowing users to store, process and analyse data easily. DBMS provides us with an interface or a tool, to perform various operations like creating database, storing data in it, updating data, creating tables in the database and a lot more.
DBMS also provides protection and security to the databases. It also maintains data consistency in case of multiple users.
Here are some examples of popular DBMS used these days:
• MySql • Oracle
• SQL Server • IBM DB2
Amazon SimpleDB ( cloud based ) etc.
Characteristics of Database Management System
A database management system has following characteristics:
- Data stored into Tables: Data is never directly stored into the database. Data is stored into tables, created inside the database. DBMS also allows to have relationships between tables which makes the data more meaningful and connected. You can easily understand what type of data is stored where by looking at all the tables created in a database.Page – 3
- Reduced Redundancy: In the modern world hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in database was a big problem. But DBMS follows Normalisation which divides the data in such a way that repetition is minimum.
- Data Consistency: On Live data, i. e. data that is being continuosly updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it all by itself.
- Support Multiple user and Concurrent Access: DBMS allows multiple users to work on it ( update, insert, delete data ) at the same time and still manages to maintain the data consistency. 5. Query Language: DBMS provides users with a simple Query language, using which data can be easily fetched, inserted, deleted and updated in a database. 6. Security: The DBMS also takes care of the security of data, protecting the data from un – authorised access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access. 7. DBMS supports transactions, which allows us to better handle and manage data integrity in real world applications where multi – threading is extensively used. Advantages of DBMS • Segregation of applicaion program. • Minimal data duplicacy or data redundancy. • Easy retrieval of data using the Query Language.Page – 4 • Reduced development time and maintainance need. With Cloud Datacenters, we now have Database Management Systems capable of storing almost infinite data. Seamless integration into the application programming languages which makes it very easier to add a database to almost any application or website. Disadvantages of DBMS • • • It ‘ s Complexity Except MySQL, which is open source, licensed DBMSs are generally costly. They are large in size.