Hello friends, welcome to Gate Smashers today we are going to start with the very first lecture of DBMS i.e. database management system, DBMS is a very important system in terms of GATE exam, UGC NET exam and other competitive exam. Even if I say a simple thing, in today's time for a B.tech student and even BCA student, DBMS is very important subject, means you can also say that it's very emerging subject, means if I talk about 6-7 years ago from today, then at that time less questions were asked from DBMS in interviews, but today's time Most of the questions are being asked from the database. The major reason for this is that all the top companies, the major MNC companies, which we call Top Fifty Fortune Company like Facebook, Google, Amazon, So whatever major company are there, All their work is going on on whom, is running on the database. All this company whose work is based on the database, so obviously they will ask the question from the database itself. So that's why DBMS is a very important subject even from the interview point of view. so we are starting DBMS, I am starting from the very initial level, so first of all I have written here database system, I am not talking about DBMS right now, the first term I am talking about here Database system. Database system, what is database system as I just told about Facebook. Even let's talk about India then Indian Railways, if we talk about IRCTC, then Indian Railways has its own database system, Facebook has its own database system, what Flipkart has, its own database system. Now there are 2 terms in that database system, one is database, one is DBMS, which means database system is comprised of two things, one is database and another one is DBMS. Now if I talk about database, what is the database ? It has absolutely simple definition, database is a collection of related data. here I am telling you in a very layman language it is a collection of related data. As the name suggests, database means where a lot of data is collected. But related data, what is the meaning of related data like we talk about Indian Railways, IRCTC has its own database, a very big database. Now in that database, What will happen in that? What happens when you log in, first of all, like the information of the train, means if you want to go somewhere, then you are searching the information of the train in it. Apart from that, what IRCTC will have, information of the passenger, which passengers, Those who have ever traveled on a train or are logged into IRCTC account. Will they have the data of the people from all over India. No, what I am trying to tell you here, that database is a collection of related data. It is not that we club any data among themselves, means Indian Railways cannot club the data of Indian Passport with their data, they have their own data base, their own database of passport holders. Indian railway people have their own data base, that's why it is related data. Now here I have further bifurcated it. Generally database is structured & call it unstructured, although generally it is three structured, semi structured and unstructured. But actually if we talk about DBMS, then today's time, It doesn't come in so much details in gate or UGC NET, but you should know about what is structured data and unstructured data. What is structured data, such database which I can store in any particular shape or in a particular structure. And unstructured means which has no particular structure like I have written a simple example here, Indian railways data or university data. Now university data or railways data, Why it is structured because there is a particular structure for them. Which structures, the most important structures are used for structured data base that is RDBMS (Relational database management system) Now I am coming here on this term database management system. Now we are talking about that we saved the data means I have a lot of data, I saved the data in the backend, in hard drives, on the servers. Now What to do with that data, obvouisly users will search that data, user want to access the data, Now they will do some updates in the data, will insert some new data, will delete some old data, means they have to perform what operation on an average, have to do insertion means, some data has to be added, have to do deletion means some data has to be deleted, have to update. Update means some old data, like address, address of a student was something else, has updated means it has changed. so we call all these things operations, Operations now I should have some system to perform all these operation, so that system we called database management system. So data base management system has collection of operations which provides easiness to the users, so that the users can easily perform the operations in the database, which operations, insertion, deletion, updation Now where can be the data, the data may be in the remote area, that means for example if I am sitting in Delhi and where is my data stored, in Mumbai. So the data, I have nothing to do with the location, I have to access the data and make some changes in that data. Means we access the data of IRCTC, we do some reservation of train. So we know where that data is stored, no. Because users have nothing to do with it, they just have to perform their operations. And the DBMS helps them to perform those operations. Now DBMS also we have various, different- different companies have been created different-different database management system like, if I tell a simple example, Microsoft, Microsoft corporation has made SQL server, Oracle people have also made different versions of SQL server 2005, 2008, 2010, 2016, various different version, same oracle has 2009, 2011, 2012 C, 2016, different versions, similarly with my SQL, its belongs to Oracle and DB2, its DBMS of IBM to manage the data, Now here we are talking about structured data, I am only focusing only on structured data out of this whole because what I told, structured data is such data Which has proper structure to store the data and that structure is relation. Relation means table, means we stored structured data in which format, in table format. Table means, even if you do not know about it, no problem, I am explaining it in a very simple point of view, means if you have seen the excel file, there are columns amd rows, you can compare that with it. Means what is a table, in which there are some columns and different different rows. Now technically we call this table, relation. But what is my point is that how we store data structure data can also have different ways but the most useable method is relation, means how to store data in relation form, in table form. Now when I am storing the data in the form of relation then obviously I also need some management system, i need some platform which support the relation. Means whenever the user access the data, it show the relation. whenever users store data, it goes and store the data in the relation, like IRCTC. Now if you remember that you have ever logged in to IRCTC, then you first check it, when you enter the source and destination, then you will get the information of all the trains, And it comes in which format, it comes in the table format, in which first column is train number, train name & also different like number of compartment, apartments, type of seats, departure time, departure date, different databases have their own columns. we're not talking about that right now. We are talking in simple format, whom I am talking about here, only structured data. Because in B.Tech which we study RDBMS (Relational Database Management System), in that all we are focusing on, on whom, the structure. In GATE also questions comes from this, in UGC NET, even in all the competitive exams the questions comes on structure data, and how to store structured data, in the form of relation. Now storing the relation and accessing it, What do I need, Management System. So what is a DBMS? A Management System, but for whom? for relation. So that's why a new term has come from here RDBMS, that is relational database management system, so this is our subject i.e. relational database management system, a system where we can perform, insert, delete, update many operations., but on whom will we perform? On relations. So this is the basic introduction of the RDBMS. I forget to explain about unstructured data actually, unstructured data means data which does not have any particular structure to store it, means there is no predefined structure where I can store that data. Why ? Because the majority of the data in the unstructured data are like photos, videos, which do not have any particular format. As i am talking about a web page, what is in a web page, web page is a collection of photos, videos, chats they do not have any particular format, they can be in any format. It may means that the web page first contains the video, then your image, then some text in it or maybe the first few paragraphs came. But structured data will always be in a particular format and what is its format? Table. We are not talking about unstructured data because our main topic is, our subject is RDBMS is working only on structure data. This is just a extra thing, I just want to explain to you. And another one point is, if i talk about today's time, 90% of the data on the Earth is actually unstructured. So all the technologies in today's time, the maximum technologies are coming on the unstructured data, But this doesn't mean that structure data is closed, structured data is also exist. But most of the technologies are on unstructured data which is being used the most at today's time, like if i tell a simple example then If we talk about big data or Hadoop, we use all these terms in unstructured data. But here i will explain only about structured data and RDBMS in further videos.