 So students in this module, we will be discussing the background and what you need to know about online airline reservation system. Because in the next module, I will talk about the logical model and the ERD model for that airline reservation system. And this background is going to help you understand that what we draw as the logical diagram as the ERD, how the things are connected. And you will be able to make sense out of all of those things. Because if I present to you directly those ERDs and those diagrams, that will be difficult to understand. Right? So that is why we will go through some of the background about the airline reservation system, online airline reservation system. Let's look at the module coverage. So I will give you some overview and inventory management. So what is inventory management? Inventory management, inventory is a seat. In the airline language, inventory is a seat. And that seat is all about in the airline reservation system. And then something which is over here PNR, which is the passenger name record. And of course, it contains some of the additional information about the passengers also. And of course, the fare code and ticketing, how the fare is decided and what is ticketing is there. And of course, we will learn more as we go and deep into this module. So let's look at this. So it incorporates the airline schedules, fares and tariffs, okay, distribution of data and GDS. So what is GDS? GDS is the global distribution system. So let me talk about in more detail. So what does this incorporates? It includes the airline schedules, fares, tariffs, passenger reservations and the ticket records. So it contains many useful things, right? So fare tariffs are there, ticket records are there, okay, and the GDS. It is the global distribution system. Now remember that in early days, the airlines had their own reservation systems. And then it was changed and deregulated. And then there are a number of companies who are the global distribution systems who are running the reservation systems and different airlines tap into it, okay, users tap into it and airlines tap into it, they all tap into it. And of course, there are travel agencies also and other indirect distribution channels also. And some of the airlines have their own for their own operation, they have their own reservation systems, okay, reservation systems. And these systems can 98% are ticketless. And there are hybrid airlines also, so you can see that we have this GDS over here. And we have these airlines over here. And we have all sorts of things, hotels are there. And car supplies are there. And they are connected through this internet booking engine. And who is accessing them, you as a traveler are accessing them, okay. And travel agents are accessing them incorporates and all of these things are tied together through this. This is the airline reservation system. This is the system which we are talking about the online airline reservation system. So this is the background. So we have internet access also and indirect access also. So what is inventory management? In the airline industry jargon, inventory is a seat. It is a seat, okay. And of course, the inventory is business class also seats can be economy class. So we have this business class also, okay. We have this economy class also and there are actually 26 booking classes, right. And they have different prices and they have different conditions and so on, right. So they have different booking classes that is understood to inventory data is imported and maintained through a scheduled distribution system over standardized in interfaces. So one of the core functions of inventory management is inventory control. And what constitutes inventory control, how many seats are available, how many seats are available status of the seats, how many seats are available and opening closing of booking classes for sale and in combination with fairs and booking conditions, okay. We add the fairs and the booking conditions. So we have this opening and closing and sale is related to the fair and the price of each sold seat is determined based upon all those things. So there's something more also, which is the yield management system, okay. So this performs permanent optimization of what of this booking classes because they have to make money, they have to make money, okay. And this responds to the changes in the demand and respond to the competitor pricing also. So this is automated, okay. This is automated, right. So this is how the inventory management works. So users access and airlines inventory through an available display, okay. This is a display over here over, okay. This is the client, okay. This is the client and it contains all the offered flights for a particular city pair with available seats and different booking classes, okay. So cooperating flights, connecting flights or legs, I will talk about this leg also. What is the meaning of the leg? If the city pair is not one on which the airline offers service, it may display a connection using its own flights or display, okay. So if this, so this you have A over here, B over here, C over here. And if A to C is not present, then this is the leg over here. I will talk more about it. The availability of seats of other airlines is updated through standard industry interfaces. So there are other airlines also, okay. So this is, this is updated also. It's updated. So what is there in PNR, personal information, meal request, say, for example, somebody says I want veggie or whatever, okay. And then there are the flight segments, issue tickets, etc. And of course, profile data to avoid data reentry, right. So in addition, most systems have interfaces to CRM, CRM, which is the loyalty, loyalty applications, they're also there. CRM is there and reservation systems. So once a flight has departed, the reservation systems updated with a list of the checked in passengers. And there are no shows also, no show, okay. And there are go shows also, go show. No show are the people who made the reservation, but did not come. And go show is the people who did not make the reservation, but they came and bought the ticket and then they left. Left means that they flew, they flew, okay. So these are some of the things which are happening in the background. Fair court and ticketing. So what is the fair data stores, fair tariffs, rules, routing maps, class or service tables, tax information, and all of them is used to construct, construct the pair. So many things are going here. Rules, what are the rules we are talking about? Rules like booking conditions, minimum stay, advance purchase, okay. And they are tailored differently between different city pairs or zones. So from A to B, it can be different from A to C. It can be different and so on. So inventory control can be used to manipulate through the availability of fields over here. Then they are air for ruling, coding, recommendations, and all sorts of things are going. So many things are happening over here, okay. So finally the role of ticketing is complex. It is very complex, okay. This is very complex. And a small number of pair tickets are still issued. The electronic ticket information is stored in a database containing the data that is the ticket number, fair tax components, and all those things. Now the purpose of giving you this background, as I said earlier, is to make you understand that what is happening behind and what is being used to solve these problems. So your task is being a problem solver. So that is all I have for you in this module. Thank you very much.