 The student in this module, I will briefly share with you the schemas for two important online systems. One is the online advertisement and the other is online reservation system. So let's look into the more details. So what is online advertisement? So first of all, what is advertisement? Advertisement can be regarded as the process of enticing you, enticing me into doing things into subscribing to certain services, enticing to buy certain products or do certain actions. So that is advertising. When we talk of online advertisement, it means that the advertisement which uses the internet, which uses the worldwide web, which uses the search engine optimization. And we will have quite a few module towards the end of this course, which discuss search engine optimization. And what is online reservation? Online air reservation systems are the systems which interact with the passengers, which help the passengers make the reservations, buy the tickets, which are linked with the database of the airlines, which look at the legs. Legs means that how the transfer is going to be made, which flights are connected to which flights and so on. A lot has happened over the years with reference to the airline reservation systems. So in this module, we will only briefly look at the database schemas for each of them. So let's go and move ahead. So online advertisement or online advertising. Early years, first online advertising was initiated when certain companies with 14 advertisers started. That was in 1994. In this initiation, we saw the emergence and public acceptance of the web as an interactive medium for growth. After 1994, there was quickly followed by a period of research on advertisers and publishers, ad formulas, and of course, billions were spent later. Billions. Okay. So current scenario is online advertisement has been constantly rising since, since more than a decade. Okay. With the number of hours an internet user spends browsing websites, advertisers have realized, okay, people are spending hours. So when they are spending hours to advertise, okay, get their attention, get their attention. Okay. And from search engine optimization to blogs and social media to stylish ads, interactive advertising tools and branding technologies, advertisers are now using a variety of tools and these are no longer effective. There are social media, there's stylish ads, there's so many things which you can see over here. A lot of things you can see over here. Then what is there in the online advertising conceptual model? We have this advertisement tags over here. So what are those tags? For example, those tags can be free. This is this attracts a lot of traffic. It could be when also. When you have these online users, their interests of users, some are in surfing. Okay. Some are in other interests. Then you have online user advertisements and the advertisements themselves. So you see they are linked together pretty much. All right. Now let's look at airline ticketing. So airline reservations, what we have over here is that it incorporates the airline schedules, the fairs, the tariff, and there are other things also. So let's go into more detail about the airline reservation. These systems incorporate the schedules, fare, tariffs, passenger reservations and ticket records. All the things are there as well as pushing out this information to global distribution systems, global distribution systems. Okay. The second type of direct distribution channel are consumers. We have consumers over here and those consumers, they make their own reservations. Travel agencies and other indirect distribution channels access the same. They are travel agencies, indirect access. And these are the consumers, consumers, reservation systems may host ticketless airlines and hybrid airlines also, ticketed hybrid airlines that use e-ticketing in addition to ticketless to accommodate code shares and interlines. In addition to the standardized GDS, some airlines have proprietary versions which they use to run their flight operations. For example, Delta's OSS, Delta OSS and so on. And if you look at the schema, you can see we have these reservations over here. These are the legs which are the links. Okay. And we have the passengers payments. So itinerary legs over here, flight schedules, so flight costs, everything is linked together. Everything is present over here. This is the point over here. So this is the conceptual model of airline reservation system. And this is all I have for this module. Thank you for your time.