Saturday 6 February 2016

DBMS- Most important topic and mostly asked questions from this topic.


Dear Aspirants,
Welcome to visit here 99SmartReview.blogspot.in. Today we are discussing most important topic in computers i.e. DBMS (Data Base Management System). And those students who are not computer backgrounds must read this. We will discuss in easiest way and in brief.

What is DBMS and why it is most important?
When we read about new topic we mostly confuse what to read and how to read and where to start the topic. When we start with good guidance we can understand the whole concept easily. We are explaining here the basic concept of DBMS,
which will clear the picture in your mind about the topic. Material on the sites are enough but how to read and what to read is always a problem. Before proper guidance and basic theme no one can understand the concept at all. A good starting is always a boon. Keep in mind these things are practically and understandable, so never rote it. And if you are serious about studies, you can easily clear all concepts.
 We usually use our account in online blogs, social networking sites, online e-banking, g-mail etc. Imagine where your data is stored? Actually data is stored by service providers and a valid username-password is authorized to access the account. Data is stored in tables, and data is secured by service providers like passwords of net-banking, account in g-mail etc.
Let’s take a simple example:
S.No.
Name
Username
Password
1.
Meera
meera@gmail.com
Meera585
2.
John
john@gmail.com
John654
3.
Meera
abcmeera@gmail.com
Meera55658

When we access our account it asked for username and password. If we type wrong and access our account, said invalid username/password. It means it checked with the data stored on the server. That’s why it is mostly used topic.
Another thing names can be same in the table then how to access that particular account?
Names can be same but g-mail account name can’t be same to all. Thus we can access particular account from the table. It means g-mail is a primary key which can’t be repetitive.
If there is no g-mail names in a table then it would be access by the S.NO, which can’t be same like our Roll. No. in a class. Again we can access particular account, called Primary key.
Similarly much more keys for different purposes which are used to perform different functions in the table. And the software to manage data in tables called database management system.
Next thing if we are storing data of different users, then it must be secure, reliable and accurate. Therefore to handle all the other operations handled by the DBMS and important for competitive exams are:

  • Purpose and Data models
  • RDBMS, ER Relationship
  • Normalization- 1NF,2NF,3NF, Codd’s rule
  • SQL(Most important) and Oracle 9i-both softwares are used to store and manage data.
  • Keys
  • DDL DCL DML
  • Concurrency control transactions, locks and deadlock
  • File organization
  • Data-warehouse, data mining, meta-data(Most important)
  • DBMS Threats and risks
  • Cryptography
  • Recovery etc.

These are the important concepts on which you have to read and understand the concepts relating with them. For Clerk and PO no need to go for deep and for SO, read and clear all concepts from basic to moderate level.
For more help and suggestions you can write us on comment section.

Thanks and have  a good day.

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