Good, good. How was your week? Just as usual, as usual, anything special. No, nothing special. But the moare going to start in February. In February already. I thought it would have been in December. That's when people do mox. I thought. I'm just surprised there in February and not December. Okay, iti know last last session I said I'd give you ten extra minutes. I have another session right after yours. Is it okay if we do the extra ten minutes next session and not this session? Is that okay? Yeah, also okay. Okay. Cool. Sounds perfect. Let me bring up your syllais. There anything you're struggling with in theory at the moment? No, not really. Okay. Do you know what your last force was on what your last section was on in theory and theory in school? Yeah logic ates and booean algebra, but you're you're fine with that, right? Yeah okay. Yeah you don't need the okay, I don't think you need more, but let's see boolean boean logic, chapter ten, chapter eight. I think you're fine. Have we done databases yet? Yeah, we've done. Yeah. Yeah, we did that last time even. Okay. I mean, we know most of the theory. Is there anything that you're really like you think you have a weak point on? Or is there something that you really not that you're really not sure about something like that? No, I actually don't think. Okay, then I'm wondering what we can do theory wise. I don't introduce something that's not in your course, but then wait, chapter three is logic gates, right? Actually not sure of these syllabus. Oh, she's doing it in a chapter. Yeah, Yeah, okay, maybe we can do chapter eight. Do you know what a dbms is? Dbms a dbms like this dbms. No, okay. I'll give you a quick kind of showing of what it is basically, right? Just starts off by telling me everything you know about about databases and what do you know about the. To store a large amount of data in a word, in fashion. Provides quick access and maccess with the c four. What give me some practical examples of where it can be used. Storing user customer data. Okay, anything else? Serving applicants for an organization or something? What's the advantage of using a database over like a table, like a file or something? Like why would I use like a dot txt? Why do I want to use a need access time, slower access time? Can you think of anything else? Less efficient in terms of storing data less efficient. So let's see. Less efficient. Kxt smaller, what else? What else can you think of? Best organized best organized as you can link link to tables or to records and and not only that, right, but this is linked directly to this and this right? Yeah. No, no, anything else. Anything else? No. Pretty you're pretty close already with this. You've got yourself three points. I would say another thing to think about is io input output you can't input an output a txt file at the same time database, you can input output at the same time. So that's just something to keep in mind. But great job. I'm I'm going to ask you now this is a bit of a new task. I want to see how how it goes. If you can write for me, I'm gonna to give you access to the to the board. If you can write for me, this is a five points question. You know, the five point question is what? Why use a database to store data? And I want you to try and reply like you would during an exam. Why would the database be more efficient to store data? Or why use a database? Basically, if you can give me five point answer in text and try to do it as you would do with an actual exam. Let me know when you finish. Okay, I just forgot how to read a spell simultaneously thing. How to spell what? Oh, simultaneously. Yeah, Yeah. The way I Yeah. All right, just to just to let you know to spell simultaneously, sometimes I can always, sometimes I mess it up. Think of it as if an American said it, they say simultaneously, right? And so then if you just spell the way that they say it in your head, you can you can spell it like that. Okay, so I'm going to grade you quite harshly because I think you know what databases are. You gave me already all the things here you get full points because you know everything that needs to be known. However, how you reply is very important. So a database has a faster access time when compared to other file types. Its data is also more organized as it is always stored in the table. At database linking tables records are pasmaking it more useful. Lastly, the database can have input and output simultaneously, unlike other files which have to switch before these states. Okay. So here the points you wanted to give me is it's faster, more organized. You can link tables, which makes it, again, more organized, but also allows data to basically have meaning and purpose. I think that's what you meant by that. I know that. You know that. So that's why I can infer t. And lastly, the database can have input output simultaneously, unlike other files which have to switch before fluid before these states. Yes. So if I were to be quite generous, this would result in four points here. I'm going to go through these one by one. So when you write about something like this, you have to think, firstly, what am I trying to give a cross to the person who's marking this exam? I'm trying to make it as easy as possible for them to give me points. The first thing to note here is that a database is not a file type, right? So maybe that's my fault. I prinmed it a bit too much like a file. A database is more like a system, a storage system, storage system. So I would not use the word here, file types, as that wouldn't exactly be correct. However, here you say, unlike other files here, I would rephrase that to something like unlike storing the data in a text tual text file, right? That would make more sense here. Another thing here is you really want to organize your words. So the database has faster access time. Why? Because it's more organized. Why is it more organized? Because records can be linked, right? So you wanna start. So that's so you've got all the right ideas, but you want na start off with that, right? You want to say a database. A database is a storage method which allows for data to be linked conveniently to be linked. This avoids words and fluffer. A database is storage method which allows for data to be linked. Due to this, thanks to this, there is no data repetition. Remember repetition? Do you remember one ns two ns et c? Yeah, Yeah so that's that's that's why but we don't need to mention it here. They don't ask for it so let's not mention it. Thanks to this there is there is little to know data of repetition. This allows or fast data access. This allows fast data access boom point Furthermore right? That's what you said but the way I'm phrasing it is different, right? A database is storage method which allows for data to be linked and organized to be linked and organized together, right? Like this here, this allows for fast data access. Furthermore, here you would say something like because here I've already said it's linked together, right? Like you said here, possible records are linked and records are possible. Debastables records are possible. Make it more useful. Yeah. Furthermore, both inputs and. Can be run simultaneously. That was good. What you put there simultaneously? Which is more practical, you say, more useful. That could also work. And the last thing here is, if it's five points, this is why I put five and not four. If it's five points here, it's good to give an example. An example of a database might be a clit's payment storage system. All right? And then this would give you five points. Five points, because it's a storage method. Linked data is linked and organized together, little to no data repetition, past data access, right? And you've got your example. And here you've got a plus one which is run simultaneously. So I know this seems you know almost pointless. You might be like, but I know these things already. The thing is, the person who's correcting your paper does not know that you know these things. So it's really, really important the way you frame it. I have had the same problem when I was younger. I would say things in the bullet point list and I would not get the points. So does that make sense? This is actually the thing that most people that should get a's, it's why they get b's, or people that should have gone to b's, it's why they get c's. It's because they're taught by their teacher and they they know these things right, or maybe they know even more. I know for my first a level, I got I got not the grade that I wi got A B instead of an a had to redo the exam because I really wanted the a but, the a star. But I got that b because I wouldn't put things into full sentences. I mean, I remember from my biology exam, right, I had a multiple choice question. In my multiple choice biology exam, I got 98%. But then I did the long answer questions and I got A C and I got a see because I would answer these long questions in not a good way. And so the examiner who would read my question, he wouldn't give me any points. And so this is why it's so important to really, really, really focus on answering these long questions. Have a strategy for them. I know it's not fun, but you just have to practice them until you're really good at it. And then it should work something like this. And once you've got the strategy down, you're really gonna na be able to get these a's and a stars because you know the content already. So that's just a lesson in life that will always be you need to know something well, but you also need to know how to communicate what you know because if you don't know how to communicate what you know, no one will ever believe that you know it, which is unfortunate, but a sad reality of life. Okay, we'll do one of these every lesson to try and practice some more. Let's move on to the next. Okay, dbms. This stands for database database management. All right. System. Yeah, system. Like heard of something? You've heard of this already? Yeah. Okay. And I just forgot the abbreviation. Okay, very quickly, just so we can cover it and call it done. What are the main responsibilities of the database management system? It can access the input and output stream. Access file, all of which file? The database file? Yeah, I so so I know when you say database file, you mean the dodb file, right? Yeah. So necessarily stored at that file type. Yeah, exactly. So I would I would avoid using file because it's technically so Yeah, like while you do have dot db file types, it's not exactly correct because that's not exactly how the database works. So I would avoid saying file type. I would say access database. And that way you'll you'll be right 100% of the time. Access io on the database of the db can use the linking functions of the database using functions of the database. Yep, using functions. Anything else? I'm looking for some kei'm, looking for some keywords. I mean, how do you say it? Where like the keyword where I don't I forgot lectors, yes. Selectors, yes. But I'm looking for some more, some keywords. Have you done this in class? You've not done this in class. No, we've done database, but not much. Okay. Okay. Then you might not know these keywords. Okay, then that's pretty good. The keywords I'm kind of looking for is access to io of database using functions. This will all relate to data management. It's so stupithese keywords, but you need to know them as when your paper is marked, you need to you need to say these things, right? And then for example, data modeling. What do you think data modeling is all about? How you change data into sort of not. Sir, how you change data to numbers? Yeah, data to numbers. That's one way of putting it. I think I would say the way I would describe it more as is organizing the data, if that makes sense. So that would be, for example, like creating a client table, client ID, for example, and like phone number. The fact that we're doing this this table is data modeling because we're modeling the clients, right? So it's basically we're turning into numbers, but I would say it's more like organizing the data. Organizing the data. To be easier x easier easier to interpret. Yeah organizing the data to be easier to interpret. So that's data modeling. Logical schema. What do you think I mean by logical schema? Let's think back to if you have two tables. Reds. What do you think logical schema might mean? I don't know. ID I D? And we have maybe a one to many relationship here. This would be the schema. So it would be how tables link together. So you might have clients payments. And this might be connected like this, right? So this would be the schema, basically how we organize the data, how we put things together to make it kind of fit together. So it would be, for example, foreign key. Know, do you know what the foreign key is? Fk. Yeah the primary key of the linker that links to the linked yes, exactly exactly. So that the fk, the the foreign key would be the one that links back to it. And where I mean by logical schema is if you're a database manager, you can manage the logical schema. Think of the database management system as the system where we create the database. So think about anything you can do with regards to data. You can manage the data by deleting entries or adding data entries. You can model the data by creating a table. You can create logical schemas by creating logical relationships between tables and data. You know, and then there's a few other points which you should know as well. There's two others data. Let me just write it text wise because my wrist hurts. Now there we go. And you've got two more, which is data integrity. What do you think data integrity is? Integrity. Our data is separated. What do you mean exactly by that conthat's containment method? It's pretty close. What does integrity mean, for example? So I'll teach you the English definition of it. Integrity means someone's kind of composure, right? So for example, if someone has a lot of integrity, then therebe someone who has a strong character but is nice. They're not going to be mean to someone else where they're not going to betray someone else. They have integrity, right? They they kind of respect themselves in their community and they don't overstep limits like someone is just nice. They have a lot of integrity. They believe what they say and they don't go against their words. They don't lie, they don't cheat, they don't things like that. That's what integrity means in English. So with that hint of the definition, let me get the official definition, integrity definition. With that definition, what do you think data integrity is? And by the way, the Oxford definition is the quality of being honest and having strong moral principles. So I don't know if that helps you with data integrity, but maybe you can kind of try and guess it. Repeat it, please. The definition Yeah the Oxford definition is the quality of being honest and having strong moral principles, basically not cheating, not lying, not being a mean person etcec. So what is data integrity? Clear. Here and you know it's honest in that it's correct. It's going to be you're never going to have false data, no false data. Yeah, right. This has data integrity, data security. What do you think that is? Security cannot access other parts of the data without reference you to it. Yes, to some parts. Let's write this down because my text is getting horrible. So this would say no access to some parts of the db, but also it would include things like encryption user groups. So that would go with no access, right? User groups. So just to let you know, let's say you have a database management system. You can create several users, like I might make user Henry, user Paul, and then you might be an admin and you might be able to access data and do things that I can't. Encryption. And what's called backups? What are backups? A copy of that file exactly. Remember, don't say the word file even though you're sometimes correct when you say the word file, please say the word a copy of the database just to get that in your head. Because if you say the word file, it implies that there's only one file. There's not just one file. And well, sometimes there is, but not always. This backups is quite interesting. So to give you some more context in Google, what they have is they have mirror databases. So theyhave like a big database like this, right? And then they're going na basically have two mirror databases and everything is updated every single day at every single moment. Ents, these three are always talking to each other to try and make sure they're correct. And they have like hundreds of these throughout the world, the world. It's actually utterly insane. The engineering of database, of a Google database servers, it's really remarkable. But basically, it's really important to have these backups because sometimes data will go missing, sometimes data will go wrong. Also, Google's money or Google's financial income comes from data. So if the data goes offline, they lose all their money. So Yeah, so that's data. Cool. Let's request to share screen and let's do some leaked code. There you go. All right, let's choose a try fucan, share the other next one. Sure. Okay. No, because this one's a bit thicker for me. Okay. Sure. Let's see schedule maintenance. It's fine. It's peyeah. We're fine, I think. All right, let's let's sort by easy ulter by easy. Sorry. Oh, maybe try reloading. All right, scroll down, scroll down and scroll quite a while, see what there is. All right, let's see. Let's click on ugly number number 263. I'm thinking of just getting it wild and then just dividing it by five. Yes, that's pretty good. That's pretty good. You might need something else though, but let's, let's let's see how it goes. I don't think it's going. You were very close with your initial with your initial things. I liked your while n mod five loop. The while is a bit less. I think it's a bit less relevant, but I see what you're trying to do. Do you want some extra hints or do you want to keep going? Yeah, I would like some all right. So have you seen this kind of formatting? If I say two to the power of three, three to power of two, five power of one, have you seen this kind of formatting before in your find facyes? I'm also trying to just find it. Yes. Well, you you've got it right here. So eight times, nine times five. And if it was smart enough, I'd do 40. 40 times nine, which actually maybe I am smart enough, is 360, right? So this would be the prime factors. Now let's imagine here for a second, you've got this number. We know that 360 is an ugly number. We know sorry, we know that it's a positive intewhich is have a prime factor than two, 35. We know that it's an ugly number, right? Because it only has these prime values. So let's imagine now we have. Maybe to pathree, we need to get to a point where we we get rid of all these prime factors, and then we are only left with this. And we check if, you know, and then this needs to be a prime factor. So we need to find x, the last prime factor. So we need to find a way to remove all the twremove, all the threes, remove all the files, and then check if there is a last prime factor. And if there is, then it's not an ugly number, right? So thinking about this and your while loop you were doing previously tried to think of a solution here. I'll leave this up actually for your benefit. And then maybe theygive you some ideas. So sort of like that, do n mod two. So mod two gives you the remainder. So if you do a mod two, so this is very close. But if you do a mod two, you're checking if the number is divisible by two, but you're not actually dividing a number by two. So I would do instead of that, I would check, is it divisible by two? And if it is divisible by two, then you probably want to get rid of it, right? Yes, a while is can be modeled by Yeah. Like that Yeah that's that's what I would do because you you get that right. So that means that if you have two to power three, three to power four, for example, then youhave two tatwo three to power four, then two times three to power four, then youonly be remaining with three to power four娘. And then I just copy this for 35. Yes, and then I just copy it for three environment. Yes. What if it's zero? What if it's zero? And what then what would you do? No factors. Yeah but then false. I would I would say let's look at the description once again is a positive integer which does not have a prime factor other than two, 35 is zero positive integer. An ugly number is oppositive. Inteviewer does not have a prime factor other than two, 35. Yeah, I'm actually actually not. Sure, maybe. Maybe test it, just put one of the test conditions at zero, and one of them is minus one and see what you get. Yeah, I think this would work. And then now n to be one right? If it's divided by five, exactly. Is so soon now? Okay. And now Yeah, it works. Thank you're good. Yeah. I mean, I mean, I don't see any immediate problems, but maybe I'm wrong. So let's let's see. There you go. Very nice. That was quick. That was really quick. He did that in ten minutes. Six. Oh. Arenthink of use variables. If you want, we can do another slide. What did he do? If n equals equals one return, if n less than one false while n motwo. But this is your submission. Oh, this is I Oh, I didn't see. For int I in 235 while n mod I equals zero. Yeah, Yeah, I guess you use seless. It's fine. You you did it anyway to things up again. Oh my God. That sucks you something. Okay. Do you want to do another problem because you did that so quickly? That's not an easy problem, by the way. People sometimes take quite long on that. So congratulations, you can be quite proud of yourself. Okay. Let's just keep going because these are all sql questions and maybe we can do one eventually. But I don't think now was the moment. Let's go for. Maybe reverse vowels of a string number 345 give some data structures. This is one where you have where I would be more comfortable in Python, but you should do it whatever language you want. And I'll try to adapt to you, but I might be less useful because I'm less good at C++than you are. I'm thinking of like a stack for shells in and out. That's a pretty good idea. That's a pretty good idea. That's a pretty good idea. I would try to think of if you want to use a stack here or more of a list, well, I'll let you try and figure it out. No, because there's the standard pair, which I can parvothe position. Yeah, that's is very, you can pair a vowel with position and then, but you need to find where you'll put it after, right? So. So if I have like my list, let's say I have whatever this here, then I would have something like a list of zero, because that's where the I shows up. So zero, you know, there's a double end. This is okay. So I can push the positions. I can make two dqs push positions in reverse order and vowels in just normal order. I like it. I like that thinking. I think you're on the right track. I've never used this before. Yeah, nicoi'll let you deal with all the C++. I think I'll just hinder, I'll just hinder you anyway. Normi just use vectors and stuff, I don't really insive. Read the. How big is this though? Three with five zeros at the end. So 300000 that Yeah. So it's how big should my data type be though? Yeah, that's that's a good question. Itbe better to use a variable sized type. I don't know if that I mean, it must exist if it's a vector in C++if they have that this, the string, Yeah, the string will be like this in and Yeah, that's the length. So the cualso has to be as big as the string. Yeah, that's can you assign? No, you can just use s dot length now has to be defined at compile time. You can just use s dot length. No, it has to be defined at compile time. So. But then even if it's as dot length, you still need to know how many vowels there are. Is there is there no variable size? Listen. There must be like a I'll see. Yeah but that's going to be pretty slow. Itbe slow. But think about it, especially on this size, it would be but think about it, algorithmically writes, it's definitely slow. Your 100% writes. But is there any other way you can do it that is faster than going through the string once and then going through the string again? Can you only go through string once? Or do you have to go through it twice? Oh, I only have to go through it once. I can input the queue and the stack both at once, which is good. Yes, you can go through it once, but that means that you don't need to. Well, actually, let's say I have this right, but how can I check my outpuagain that standard out? I think that's big enough. Yeah, that's definitely. No, I should use that. It is. I can, you know. Does that make a difference? I hope now how we know it's. I'll use this for now, though. You're thinking of just looking at the ascii table, trying to find the value, corresponding value, and then comparing if it's in slids of vowel and then added, Yeah, that's exactly what you should do. I like that idea a lot. Maybe there's A C plus plus function to see if it's a. Like you could always turn it to lower, right? Because this is what it expects me to output this again. Yeah, Yeah that's why I'm doing it that it's Yeah there's too capital or too lower. Yeah, I know your right. But absolutely, absolutely right. Yes. Oh, way that helps. Yeah, that's it, really. Bless you. All right, Henry, I'm afraid I'm going to have to end the lesson here as I have to join another session very, very shortly. But as usual, great job. You keep you keep getting better and better. I think for this leads code, if you want to do it by yourself, go ahead. I think you've got it. I mean, I'm watching you do it now. I think I think you've got the right intuition. Perhaps next session we can do more long answer questions. I think that's your biggest weak points. You've got everything. You've got the know how you've got the logic, you've got your smart so you can actually get good grades and you've you've got everything right. You've got everything but the way you answer questions is just is not really how how markers want to be into practice on Yeah, absolutely. I mean that's that's your main weak point. Everywhere else you're you're almost out of ten and we can keep practicing those and we can keep pushing you further. But but I think the long answer questions is where we're gonna to have a lot of benefits. So maybe next session, I know it sucks because it's not the most interesting, but maybe next session we're just gonna to do some long answer questions and we're just gonna to do them until until you're good if that works for you. Yeah a whoops, perfect. Apart from that, like you're doing great, you're doing more than a level. Your your leds code skills are there. So I think whatever ever you want to do computer science in your life, I think you'll be quite quite good at it. So once again, great job. Have have a great week and I'll see I'll see next session. I'll give you ten extra minutes if that's okay. Yeah, all right, mama Henry, so see you.