 Dear students, in this module, we will look at the four reasons why databases are connected to the web. What are the four reasons? So let's go through those reasons and those applications and those examples. So this is the module coverage, right. And as you can see over here, these are the four reasons or the examples for placing the data or connecting the database to the web. Now there are certain things which are common or when you go about doing these things so that things or that set of things are covered in the first point, which is the publishing data on the web. Now remember that web is something new as compared to the databases which have been around for a longer time. So the data which is available there that is not collected or that has not been organized and that has not been recorded in such a way that makes it efficient for connecting to the net. Now what are the typical characteristics of that data? That data is of large size, lots of data is there and of course the queries which are there which you are looking for in some cases the end users of the prior era before the web, they may have the queries. Of course they had thought about it but the thing is that you might not be able to get the queries for your web application. So that is one thing and of course if you cannot develop those queries or if you cannot get those queries from the database people then is a big problem. And then is the the number of results because there's that data set has not been developed for a web environment. So you may be getting not hundreds of results not thousands of results may be hundreds and thousands of results. That is one thing but that is very unpredictable. The other thing is that the nature of the results. You might be getting results which are unexpected. Why for I give you one example you are looking for something say zebra and you're getting the results about the zebra as an animal and you might be getting the results about zebra as in the zebra crossing. Now you understand what I'm trying to say over here and of course in these scenarios it is the user who is entering the search criteria. There are very unlikely to be any buttons of course that predates the web. So when the user enters the text in a search box and gets the results now the user has to navigate in the results to get what the user is looking for. So now let's go into more details about those examples and applications of connecting the database to the web. Now one is the simplest one is sharing of the data. Now we would like to share the data and the data is small in the data set. It is very simple. It could be office memos and that data set could be queries and those kind of things. So it's a simple database and it is not very large. It doesn't consist of hundreds and thousands of transactions and you can develop that database on your own. Okay. And the query results are also predictable. It means that they are not going to be hundreds and thousands. Why because that is not the number of the office memos which are being searched. Number one. Number two that the words which are there which are being searched they are the comprised the standard words which are used in office environment. So there is very little unpredictable part right. So sharing of the data. Then is the e-commerce. Now if we are looking for the e-commerce now in e-commerce we have the type of features which were there in the old systems and which were there in the recent systems which were developing a database for sharing the office documents. So we have the data about the transactions about the customers and the data about the products also. Now of course the products the number of products is not so large as compared to the number of transactions. So these are the common things. Now there are other things which are different in an e-commerce website or when you want to bring your data for an e-commerce application there are three things over there. One is the security. The transactions have to be secure because it involves the money it involves the transactions the products also. So number one is the security. Number two is that when we are looking at a transaction a transaction consists of multiple actions multiple processes. So the web application this has to handle those transactions also and then of course is the hardware and software failure because the user who has placed an order right and who has entered his or her credit card numbers also. Now that user believes that the transaction has taken place. Now if that user doesn't know what is happening behind so behind maybe the operating system crashed maybe the hardware crashed so that has to be taken care in this e-commerce application. Next is keeping the pages up to date keeping the pages up to date. Now what is this basically is that we are communicating or we are sharing the data the information about our organization or your organization with your potential or your current customers. Now in that case the database is almost invisible to the end user. As a matter of fact it is irrelevant for the user to know that there is a database at the back end or not. You are just communication the information about your products and your services and of course this is not a complex thing you can design it for yourself by yourself also. You just have to ensure that it contains or it covers the basics of the database and then of course one thing is for sure because the strength of this application is in the database so you can populate your database and you can generate these pages dynamically. Now one thing to be ensured is that there should not be unexpected error messages which are displayed to the user because that will annoy the user and the user will think what is the purpose of using this site or using this application or link to know about the organization when it creates creating problems why not get it from a catalog or why not go somewhere else. And of course finally general database needs. Now remember that as opposed to a desktop application right which may have cursors sensitive cursors or insensitive cursors a lot of joins and a lot of complexities. Your web database application if it does not have these kinds of complexities of course they can be there in exceptional cases then you only need a simple database and a reliable database manager OK. Ensure that your database design is OK. It is simple. It is just like a filing system in which you can put the data or the files and retrieve them. And what you have to be careful which of course the user is not should be knowing is that where are you going to host your application and how it's going to be running and what would be the backend what would be the application server the database server and the web server. To that is all I have for you in this module. Thank you for your time.