 So, students in this module we will look at some of the features which are not common among different NoSQL products, not common. It means that there are NoSQL solutions or products which have number of common features but lack certain features which we will discuss in this module, but they still qualify to be NoSQL database. I think you understand what I am trying to say over here. So, let's look at more details and let's look at the module coverage. So, this all started as open source and there are issues with open source vis-a-vis the commercial organizations. So, I will explain this in this module. Then is base versus acid. Now, this is not a chemical or chemistry course, acid is an abbreviation of something and as opposed to acid there is base which of course I will discuss in this module. So, you don't have to worry about it and then what are the features the mission critical features which enterprises are looking for in a NoSQL solution. What makes a solution which is acceptable by the enterprise? Enterprise is a large organization. It's a multinational, it's a global organization. So, I'm not getting or giving any names about an enterprise but I think you get the picture. So, let's go into more detail. So, open source. Now, what happened was that when the developers had a problem, they looked around and looked for NoSQL open source solution and when they could not find a solution they developed a solution of their own and made it public. So, as many problems are there as many solutions are there and they are public and they are open source. Now, what happens is that lack common features required for mission critical businesses or mission critical operations. What I'm trying to say over here is that since they were developed for this problem, for this problem, for this problem, so they did not have the common features which are required for a mission critical enterprise and those features were there and which were being developed by commercial organizations. So, over here we have this open source and over here at this end we have commercial organizations and in between is the gap why this module is here. Now, therefore, now if you are a developer or if you are a chief information officer or a chief technology officer you should be aware of the total cost of ownership because you might get an open source NoSQL solution but that solution may not have the features which are required in an enterprise and there should be and there could be a heavy subscription fee and when you pay that fee then you get those features. I think you get the picture. Now, base versus acid. Now, what is acid over here? Acid is in abbreviation. It is atomic. A stands for atomic. So, when the transaction is going it goes on and it gets completed and C is for consistency. It means that whatever different users read they read the same thing which is valid and isolation is I. I means that the transactions don't interfere with each other and durable means that when the data is written to the database that data stays there and that data is not lost. Now, surprisingly acid this acid compliance this is acid compliance. This acid compliance was not there before 2014. It means that the NoSQL solutions were there but they did not had or they did not complied with these four requirements but even still today there are some NoSQL solutions that are serializable acid. It means that they are not classical or they are not standard okay. They are not standard acid. Okay. And so over here we talk about the base and in the subsequent modules I will talk more about the base. What is there in the base? So base is as opposed to acid. I will explain this. You will get the picture. So let's move ahead. So what the enterprises are looking for in a NoSQL kind of a solution. So what enterprises want? The enterprises want high availability. High availability means that the system the application on which that NoSQL solution it is robust. Okay. It is available. It does not crashes right or it does not crashes suddenly right and disaster recovery and when it does for example the system crashes the application crashes or somebody outside the cable company is digging a hole and they cut the cable then the system can be brought back. It can be brought back without loss or without loss of information without loss of data with minimal disruptions, continuity and support. Support means that there are people who can advise who can tell and the best practices can be provided by the services people who can tell who can advise and of course there is an ecosystem ecosystem that they are partners they are developers they are people who are developing things and which can be plugged in which can be patched up. So the application keeps on running which is developed on a NoSQL solution. So how NoSQL used by enterprise. Now if you go to the website of 250 plus NoSQL solution providers you will see over there that they will claim rightly that our solution is used by an enterprise. So that is not the point. The point is that how that enterprise is using that solution just using NoSQL does not qualifies it to be enterprise compliant. Okay. Unless unless and until that NoSQL solution or product is used in mission critical domain of that enterprise. Right. And that is why NoSQL is used for speed in an enterprise for speed. But the critical data. Okay. The mission critical store is in a relational database management system. So NoSQL is providing speed but the data security is in the RDBMS. So that's all I have for this module for you. Thank you.