WB JECA 2026 DBMS Previous Year Questions | Rank 1–100 Strategy

本站添加: 2026-05-15

[00:00:00]Hello friends, welcome to CSGenix Bengal YouTube channel. In today's video, we have brought you again the DBMS series PY Q for your JEE 2026 preparation. Let's solve a few questions today and see what kind of questions come from the generic DBMS topic in our JEE. First question based on DBMS. Choose the correct option for composite attribute. Who is composite attribute?

[00:00:22]Composite attribute. Kind of attribute.

[00:00:29]Which is combination of multiple simple attributes. As it is, your phone number.

[00:00:34]Phone number. Yes, you can tell the phone number. How can you tell?

[00:00:36]One is your STD code and the other is the number. Okay, phone number can be a composite attribute.

[00:00:44]What can be my apartment phone number?

[00:00:46]I can divide my name into first name and last name and then middle name. If I can divide down the middle, then that is also a composite attribute of mine. Okay, edge is derived attribute, birth date, generic birth date. So, what's the deal with your birth date? You can say that the date is your birth date, day, month, year, etc. But the most convincing thing here, in my opinion, is the phone number. Can anyone tell me why an address ca n't be called something? Addresses can be divided into parts.

[00:01:15]But conviction doesn't come in the same way.

[00:01:17]So since it is an MCQ, not an MSQ.

[00:01:19]I ticked the phone number. In DBMS what do you mean by a tuple?

[00:01:24]Tuple means, let's say I have a DBMS, a table, let's say there is a roll, a name, and let's say there is a mark, let's say roll number one, name is A, mark is 90, roll number two, name is B, mark is 88, then it's not A, it's a tuple, B, 88, it's a tuple, if there is only a roll, then it's this column, it's called a attribute, if there is only a name, it's a attribute, if there is only a attribute, then the columns are attributes and the rows are tuples, then one row, each row, we call it a tuple, let's look at the next question, let's look at the next question, row indicates a dot in relation algebra, selection, selection is denoted by sigma, projection is denoted by pi, and row is denoted by rename, join is denoted by symbols like this, okay, then obviously row means rename. The name of a table. You can set it with a new name using Row. Normalizing is the technique to organize data in a database to eliminate redundancy. Maximize Minimize Average Diffuse. First of all, can redundancy be completely diffused? Destructible. So in this case, the most correct answer is minimize. We want to normalize the table to reduce redundancy.

[00:02:49]What are the different forms of normalization? And NFT NF.

[00:02:53]Okay, the stage is increasing, three NF BCNF for NF and giving is OK.

[00:03:02]This is our technique of normalization. Okay, let's look at the next question in DBMS. Let's look at the next question in DBMS. Relation is having dosh normal form if it contains tomic value. First of all, what does this word really mean? It means it is not written properly.

[00:03:23]What is the concept of BBMS? This is of course given the conditions of first normal form. I mean, in my case, if I were a student, what subjects did that student take?

[00:03:33]Yes, guess what subjects he took after that.

[00:03:39]A student has taken Physics, Chemistry, Math, and Biology. If you write Dhar, the roll number is one. And if you write Dhar in the subject, it is PC MB. So here the value of the subject is becoming a multivalued attribute which is not allowed.

[00:03:54]How do you have to write to be one NF? Is the roll okay? End subject. So roll number one, subject is physics, roll number one, subject is chemistry, roll number one, subject is mathematics, roll number one, subject is biology. This is how it should be written.

[00:04:10]Then it will be One NF only when every attribute is a single- valued attribute. Not a multi-valued attribute. So the most correct answer is first normal form.

[00:04:24]Let's look at the next question. Let's look at the next question. Choose the correct options for functions of DBMS.

[00:04:31]What functions are available for DBMS? So the first thing is concurrency, not shareable databases. So look, it's written Category Two. Okay? So what does Category Two mean? These are MS Q.

[00:04:41]Okay? There may be more than one correct option here.

[00:04:43]So if you go to a distributed database, then obviously concurrency is one of your properties. There shouldn't be a non-shareable database. Because databases should always be shared. Backup and recovery is a must-have. And you must have a database schema. What does schema mean? You should definitely have a definition of your table in a database. So this is my correct option. Although when the questions were asked, what should I say? Half means filled with half info. So that's why I'm not saying it too strongly. You have to think about it this way.

[00:05:18]Select the correct options regarding union and union all in index.

[00:05:23]Union Remove Sorry Union and Union Escol. Union Remove Duplicate Rows. This means that if there is a duplicate in two tables, you will only keep the duplicate once. Okay? That's correct. Union does not remove duplicate rows. This won't happen. This time the union keeps all the duplicate rows.

[00:05:43]Then both option A and option D will be correct. These will correct your multiple options for MS Q.

[00:05:51]Now let me tell you something, if you attempt MS Q and get one of the three correct answers, you will get partial marks. Which is not available in GATE or other exams. Everything has to be done there. In which case, if you do the exam partially, you will get partial marks.

[00:06:06]Let's take a look at the next questions.

[00:06:08]So let's look at the next question. In case of union compatibility, if you want to union two relations, the two relations must have the same set of attributes.

[00:06:19]Okay? Both should have the same set of tributes.

[00:06:22]Relationships can be any set of tributes. Two relationships must have different sets of tributes. No relationship and union are compatible. Now the question is, what is the difference between this set of tributes and the same set of tributes? The two relations will have the same attributes.

[00:06:38]The rest of the ones I want to make union compatible will also have this type of attribute. It would be nice if there was such an attribute. The two may have the same attributes.

[00:06:47]A particular relation can have any attribute it wants. Then it could be correct according to that logic.

[00:06:51]But since this is an MCQ again. This is not Category Two.

[00:06:56]So in this case it is not SQ.

[00:06:58]Because there is no point in pressuring us. Let's see the next one. Which option cannot be used with ALTER TABLE command in SQL?

[00:07:06]Okay, in the case of ALTER TABLE, we can add, drop, delete, modify, and delete columns. If we want to delete, we have to delete the table row-wise. ALTER never deletes the table rows. The basic structure of the table is what we do. So here, since we have the correct option, we can't use it. So, what should be our correct option? The correct option should be DELETE. Let's look at the next question. Okay? Let's see the next question. Third Normal Form Remove Dashes from a Relation. What does it remove? So the point is, what does our first normal form do? Holds atomic values.

[00:07:44]What does second normal form do?

[00:07:46]Removes partial dependencies. What does Third Normal Form do? Removes transitive dependencies.

[00:07:51]Okay?

[00:07:52]What does transitive dependency mean? No non-prime attribute should depend on another non-prime attribute.

[00:07:56]Okay? So let's select transitive dependency for a minute and decide.

[00:08:07]Then transitive dependency option C will be my answer here. So, these are the ones that are more. Of course, if you have any questions, you can also practice by looking at them. But more over, which I mean, questions that are not very tough for you, if you continue the practice properly, look at the PYQ and if you read the subject book properly, there are many books in the market. I won't talk about all the books.

[00:08:32]But I would say that if you also read your subject book thoroughly, it should n't be too difficult to do better in JEE. If you read it correctly. So that's all for today.

[00:08:44]See you again in the next video with some new content. Thank you very much.