 The title of this module is kind of not very exact and precise what is going to be discussed in this module Why I use this title because as for the textbook timing and performance Timing over here means the time to generate the web page, not the timing of kind of synchronization or when what is required to happen And of course performance is the response So when let's look at the what we'll be covering over here Timing and performance, transaction processing and data and nothing but the data Now one thing is obvious that once you are generating dynamically a web page It is likely to take more time. It is likely to take more computing resources Because the process of page generation has been automated Now the old timers who are used to hand coding the web page they say oh I we told you it takes more time It takes time but the overall time taken is less The experience of a dynamic page the feel is much more than that of a static page That's going to more detail It may take overall more time but the total time is less More is less More is less Interesting The feel of the dynamic page is tremendously more attracting and involving as compared to a static page A static page is better than non-graphics that is the difference over here That's the difference over here So obviously we are automating the process of page generation We need computing power but we have to play smart Instead of computing power we use the adaptations There are three different types of adaptations What the adaptations will do is that they will be accessing the database Without the user knowing that the database is being accessed to generate dynamic web page Without using a high power web server or a database server Of course the client has to be thin The processing is limited which is done at the client end So let's go into more detail A complexity of database driven website is less than the static ones Why? Because if I have to make a change in a dynamic database environment I only make a change at one place And then that change is reflected whenever a new page is generated When I am using a hand coded page I am bound to make mistakes I am bound to make typing errors I am bound to overlook things I am bound to make mistakes, miss things So this automating is less complex Cost of required computing resources has been increased It is automated, that is why But in a cloud environment that cost is amortized It becomes economical Let's go into more detail Interface adaptations Why go for expensive hardware? When you can use the frames We have a frame which is covered in a web engineering course Or a web programming course And in that frame we have data coming from a database dynamically generated This certain static header also So while the dynamic page is generated That static header is displayed And while the user is reading that static header The dynamic page generation is complete within the frame Without using expensive hardware Redirections Redirections is that I type a URL or I click on something And the website has moved to other place And as I am taken to that other place From the old domain to the new domain During that time the dynamic page is generated And set the home page I have this intranet And people click on my home page And while my home page is being displayed Which has certain static things For example my name Which of course is static title department Which might be changing And while that is being displayed The dynamic content is also being generated And the page is being populated So these interface adaptations Don't require expensive hardware But they give good performance Kind of a feeling of good performance Okay Transaction processing What is transaction processing? Transaction processing is a collection of operations Which will go unstopped That is why it is atomic It either succeed or fails The purpose, the objective is that the data base Should be in a consistent stable state If it fails it rollbacks to the prior or initial state If it succeeds The change is becoming permanent Now this transaction processing Can be implemented at different levels You can specify the operations You can set the desired level And you can create your own transactions also Lots of flexibility over here But remember transaction processing is expensive Why? Because operations may be implemented twice Or even thrice Remember in the prior module I showed you how database programming works Remember the testings Remember the tests To multiple tests happening For the same thing So you have to be careful about Because this will hinder the performance This will degrade the performance And ensures commitment or rollback Of course commitment If it's successful rollback If it fails Evaluate the need for rollback If the rollback is not required You don't have to implement rollback Why make preparations? Why code something which is not going to happen? Because the rollback will always degrade performance Remember that you are going to retain your customers You are going to have happy customers If your application is running fast Right? And you have to make your application run fast The smart way Not the expensive way And remember data retrieval never require rollback You don't have to implement rollback in data retrieval Rollback is required Either you modify the data You insert the data Which is kind of modified and delete the data But if you are reading You don't have to implement rollback Because in reading there is no rollback And finally Data moving from HTML to databases People are populating the databases From the static data which is available on HTML And the converse is also happening Data moving from the databases to the HTML pages That is happening But remember one thing This happens or this happens Right? You enter the data into an HTML page is very easy The tradeoff is that maintaining is very expensive You enter the data in a database That takes slightly more effort But using SQL queries or other queries You can update, modify, delete the data Very effectively, very efficiently With rollback and commitment So you have to look at the long term benefits Versus the short term benefits And you should be always centered, focused Interested on data and nothing but the data That's the message of this module Thank you very much