Introduction to Database Management Systems

hello everyone and welcome to the course of database management systems or in short we call it as dbms in this video we will be seeing the basic introduction to dbms before dbms we were using the file system approach in the later videos we will see more about file systems and why we prefer dbms approach over the file system approach before we get into the topic let us see the outlines or the topics that we are going to cover in this video the first one we are going to see is the basic definitions or the basic

terminologies that we need to know next we'll be looking into the definition and functionalities of database management system and then we'll be discussing about the properties of database next we'll be briefly looking into an illustration of a simplified database system environment and then finally to understand database and its functionalities better we'll be looking into an example of university database so as we discussed first we'll be looking into the basic definitions in relation to dbms the first one is data data is any raw facts or unprocessed facts that you can record like for example any numbers

name of a person name of a place any kind of text images audio video etc all these are called as data next what is information these unprocessed facts or otherwise called as data when they are processed to make a meaningful context then that is called as information or in other words i can say it is the processed data like for example the age of suresh is 25. so here i take the raw facts or the unprocessed facts process it to make a meaningful context and that is called as information next let us see what is

a database database is a collection of related data now a random collection of data or data that is not related cannot be referred to as a database it has to be a collection of related data like for example the data in an online banking system database has to be related to that particular bank similarly the data in library management system database has to be related to that particular library so this is what we call as a database the next one is metadata metadata is nothing but the database definition or in other words i can say

it is the complete description of a database or it defines the database information like the storage format or the data type of the data that we are going to store in the database or the constraints on the data all these information is called as metadata so these are the basic definitions we have seen in the further videos we will see more definitions in relation to dbms next let us see the definition of database management system database management system is a system to manage the database and here managing could be either storing of data or retrieval

of data from the database now let's look into the proper definition of database management system database management system is a system or it is a software or i can say it is a collection of programs that enables users or that allows the users to create and maintain the database so this is a very simple definition now let's move on to the functionalities of database management system database management system allows users to define the database to construct the database manipulate and share the database now defining the database involves specifying the data type for the data that

we are going to store in the database also specifying the structures and constraints for the data now constraints is nothing but the limits on the data like for example if i have age as the data to be stored then i can have a constraint say age greater than 18 so only if age is greater than 18 then only that data can be stored in the database so that is what we call as a constraint the next functionality constructing the database is nothing but the process of storing data on some storage medium or in other words

i can say it is a storage of data so when data is stored a database is being constructed the next functionality manipulation of a database includes functions like querying the database to retrieve or to get any data that the user needs it also allows users to update the database and for generating reports the next functionality sharing the database allows multiple users and programs to access the database concurrently or simultaneously or in other words i can say many users can access or share the same database at the same time in an efficient manner so these are

the main functionalities that dbms provides the other functions provided by dbms are protection of the database from unauthorized access or from hardware or software failures and also maintenance of the database for a long period of time so that is with the functionalities of database management system next we will be discussing the properties of database there are three properties of database the first one is a database represents some aspects of the real world or otherwise called as the mini world so anything in this mini world the objects their properties the relationships between them all that is

represented by a database and if there is any change in the real world that change will also be reflected in the database the second property is a database is a logically coherent collection of data with some inherent meaning so as i said earlier a random collection of data or unrelated data cannot be referred to as a database the data in the database has to be related or logically coherent the next property is a database is designed and then built and populated with data for a specific purpose so these are the three main properties of database

the first one is a database represents the real world secondly it is a logically coherent collection of data and thirdly a database is designed built and then filled with data for some purpose next let us look into an illustration of database system environment so here we have the users or the programmer who writes queries or programs and these queries or programs are processed by the dbms software and then based on the processed queries dbms software accesses the stored data in the database that is it accesses the stored database as well as it accesses the metadata

as we have already seen metadata is the database definition so this is a simple illustration of a database system environment where users write their queries and it is processed by the dbms software and based on the processed queries dbms software accesses the store database as well as the metadata as we discussed in the outlines finally to understand a database and its functionality is better we'll be taking an example of a university database that stores student and course information so here i have taken three tables the first one is the student table which holds information about

the students in that university the second table is the course table which holds information about the courses available and third table is a grade report table which contains information about the grades received by each student in a particular course as we have seen earlier the four functionalities provided by dbms let us try to understand those functionalities better with this example as we learn defining the database involves specifying the data type structures and constraints for the data that we are going to store in the database so here specifying the structure of each record means specifying the

different types of data elements present in that particular record so here we have three records the student record the course record and the grade report record and these columns are called as data elements in each record now specifying a data type would be now for example for student name i can say the data type should be a string of characters or for data element role number i can say the data type should be an integer and so on and we've already discussed what a constraint is i can give a constraint on the student name saying

that student name cannot be null so this is all about defining the database the next functionality constructing the database is nothing but storing data so once data is being stored a database is being constructed the next functionality is constructing the database which is nothing but storage of data so when data is stored a database is being constructed then we saw database manipulation as the next functionality which involves querying and updating the database examples of queries would be listing all the students in the cs branch in that university or listing the grades received by a particular

student in each course and then we saw sharing the database where this particular database can be shared by many users at the same time in an efficient manner so this is a very simple example of a database that i've taken to help you understand what a database is and also to understand its functionalities with this we come to the end of this video hope you all have understood the basic introduction to dbms thank you you