The types of data there can be mainly two types of data qualitative and quantitative normally qualitative data are like feelings like uh as I have given you it was great fun we cannot actually measure that how much fun is quantitative data is given by figures but it can be measured also anyhow it can also be divided into two main categories the first one is discrete where you can explicitly say the amount and the other thing is continuous the continuous means is very difficult to see the actual value you can express with floating-point numbers I have asked one question out of this feeder so what would be the answer for this what is your answer if somebody has a question like this can you figure it out and say the data is not you can justify your answer it’s better if everyone can go through this and identify because it’s better if you can identify it by yourself with the things we discussed since you all I think all of you answered.
What is a database then how can we identify a database then you can come to your conclusion if you are not certain what about the answer for this one can we use Excel as a database I’m asking whether we can use Excel as a database not as a database system actually we can if you can quickly go through the text in my presentation and if you can recall the things we discussed we can use this as a database, but there are some disadvantages of using excel, uh if you look at small organizations small shops they use Excel to record everything, yeah they are business transactions and everything is recorded on Excel sheets, but there are uh many other tools like Microsoft access provides a small level database system actual database management system very primary level database management system for a small piece of work but still they use Excel that is why I ask you to actually get the main concept into your mind if you get the concept into your mind you can easily answer.
If you look at this exercise it is having a collection of information related to a particular subject so most probably something like a staff employee registration system or employee details right so we can think of it as a database anyhow there are some differences between excel and type of databases we are planning to learn throughout this lecture series I have listed down some disadvantages of using excel as a database even though some small level organizations still use that one thing is it’s not easy to query data and concurrent access as I told you it’s again like a file but you can implement relationships in between worksheets, not workbooks right in normally one excel we call once we open the Excel it opens as a book right we call it to excel book with Excel book you have many excel worksheets if you look at the organization of the Excel so likewise separate tables.
You can create separate worksheets and create your tables there then you can come up with a database and if you want to use Excel there are many ways of linking the worksheets in between right there are formulae you can link in between but you cannot link among the workbooks the other thing is uh it is very difficult for you to handle a large volume of data you need a lot more time to search and find records in an Excel worksheet if you look at the typical real-world scenario now you just as you you are inserting your ATM card to a teller machine so I think you have experience in doing that how long would it take actually to validate your pin does it take hours days weeks how long does it take to identify you out of millions of clients so do you have any experience credit card validation so if you take a credit card like HSBC they are international they are in international banking, therefore, they have many millions of clients around the globe even at the instant.
You try to validate a credit card it is validated within split seconds right it does not take much more time to validate and you want to if you want to check the balance account balance the credit limit whatever it is just a split second but you think the whole number of clients the population is millions so you can think of how fast it happens to do that it has to go through the network and network traffic and with everything it uh uses the result within split seconds not only the access time to the traveling time of packets everything together it won’t take actual time things are difficult using excel and final processing systems I think it’s clear to you so I have given you one comparison what we have discussed you can quickly go through I know what we have discussed is given in separate comparison but you can quickly go through the slide and try to understand I’m like to ask you one question regarding this uh database transactions.
Have you ever experienced regarding this role that has any one of you experience regarding this crawling make a transaction actually I have given you a situation where you can see the rollback thing happens like a power failure now we just think you have to type your p number and check the account balance and you are going to withdraw some money then at the last moment that can be a power failure normally ATMs are running for a few minutes with power backups but anyhow the system may sometimes malfunction before you retrieve the money so it always keeps on writing what the transaction is happening in a locked sheet so if you have not withdrawn money at the last moment so if you crawl back and it will again credit the amount to your account otherwise after you press ok for final verification then your account has been deducted right with the money you the value you entered but it checks whether the transaction process completes?
If it is partially complete then it will roll back right there will know any partially completed transactions the transaction has to be completed as a whole single unit that is a property of transaction, so that type of things can only be done with databases these are the last points regarding spreadsheets bus databases you can quickly go through that we will talk about the relational databases by next week do you have any questions or we can wind up for today so be sure do you have any questions regarding this so what is the example for recurring tools for database actually uh in database management system itself sometimes we give you some recovery tools like uh so if you look into administrative tools in a database management systems you can go to Microsoft SQL and go to administrative tools there are ways of having backups it’s one way of recovering as I told you so if your database administrator.
Actually, this is one of the duties to use administrative tools given in the database management system to maintain the database robustly with that they have a different set of tools given so excel does not give you only uh your file is crashed they can give you someone single recovery option once you started that program it shows you your file could be recovered it depends on what you have actually saved but in database management systems there are timely backups can be scheduled and you can recover from that backup it depends on different database management systems you can just search on the internet and find what are the features given in that particular language if you want if you are interested in uh learning that normally we are not going to use third-party tools to recover uh database management systems rather than they give their own set of tools it is duty of database administrator to use that tools and make the database in a robust.