Refresh your BTech/BE CS/IT books -1

@cemember-PlqlWH • Oct 23, 2024

Oct 23, 2024

1.0K

Hello everyone,

The idea for this thread is to refresh your old things/concepts studied in BTech/BE . May be of help to those who are working in MNCs but forgetting things day by day after doing rubbish work as well to those who are preparing for jobs specially in IT industry.

Rules:

Read each and every rule clearly.
No kind of spamming and rules breaking will be tolerated here. 😐
Everyone is free to answer the same question again even if it is correctly answered by soemone else.
Try to give options while asking questions so as it makes easy for newbies(Can call First Year students) to make guess.
If possible give possible explanation with each question or any other related information so as people can learn more things from just 1 question.
Mention the topic of subject before posting the question.
Wait for me to start next thread as soon as this thread reaches count of 30. Don't post anything once count reaches 30.
While answering please copy the question also so as to make the things look clearly.

So here goes my first question [Take my question as an example for template to be followed for posting questions in this thread. ]

Topic: SQL
Qn: GROUP BY, ORDER BY can be used in WHERE clause ?
a) True
b) False.

[Again: Avoid spamming and post count to reach more than 30.]

Thanks !

Like 0 Replies 8

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shalini_goel14

@shalini-goel14-ASmC2J • Jun 12, 2009

Topic: SQL
Qn: GROUP BY, ORDER BY can be used in WHERE clause ?
a) True
b) False.
Ans: False.

As WHERE clause is used to specify the conditions on the basis of which query should be executed and for GROUP BY , HAVING clause is used to specify the conditions.
[PS: Feel free to correct me if wrong].

Topic: Datawarehousing
Qn: What are the categories of OLAP tools(Online Analytical Processing) ?
shalini_goel14

@shalini-goel14-ASmC2J • Jun 13, 2009

*bump *

Hey where are CS/IT CEans ? No one knows the answer of my question. Is it so difficult? 😔
debu

@debu-62iszV • Jun 14, 2009
shalini_goel14
Topic: Datawarehousing
Qn: What are the categories of OLAP tools(Online Analytical Processing) ?
Hey guys! I'm not a BE/BTech CS/IT, I hope you don't mind my answering your question.
There are:
- Multidimensional (MOLAP)
- Relational (ROLAP)
- Hybrid (HOLAP)
- Web Based (WOLAP)
- Desktop (DOLAP)
- Real-Time(RTOLAP)
Please correct me if I'm wrong anywhere.

Regards,

Debu 😀
shalini_goel14

@shalini-goel14-ASmC2J • Jun 14, 2009
debu
Hey guys! I'm not a BE/BTech CS/IT, I hope you don't mind my answering your question.
There are:
- Multidimensional (MOLAP)
- Relational (ROLAP)
- Hybrid (HOLAP)
- Web Based (WOLAP)
- Desktop (DOLAP)
- Real-Time(RTOLAP)
Not at all. You are absolutely right. Even I read only first three in my BTech but you told me 3 more. 😀

Thanks !
manusaluja

@manusaluja-BMWMnB • Jun 15, 2009

OK, one question from my side on DataBase...

Why is a UNION ALL faster than a UNION?

very easy one guys... .
shalini_goel14

@shalini-goel14-ASmC2J • Jun 15, 2009

manusaluja
OK, one question from my side on DataBase...

Why is a UNION ALL faster than a UNION?

very easy one guys... .
UNION ALL is faster than UNION because UNION ALL simply fetches all the records(including duplicate rows) from two queries into single result set while in case of UNION first all records(including duplicate rows) are fetched into a single result set and then duplicate ones are eliminated. UNION creates temporary table with index just to eliminate duplicate rows.

Right?

FYI,

UNION and UNION ALL is an operator in SQL statements which is used to combine results of two SELECT statements.

UNION: It is used to select distinct values from two tables.
UNION ALL: It is used to select all records(even duplicate) from two tables.

Can check this also for more information: <a href="https://www.w3schools.com/sql/sql_union.asp" target="_blank" rel="nofollow noopener noreferrer">SQL UNION Operator</a>
manusaluja

@manusaluja-BMWMnB • Jun 16, 2009

shalini_goel14
UNION ALL is faster than UNION because UNION ALL simply fetches all the records(including duplicate rows) from two queries into single result set while in case of UNION first all records(including duplicate rows) are fetched into a single result set and then duplicate ones are eliminated. UNION creates temporary table with index just to eliminate duplicate rows.

Right?

FYI,

UNION and UNION ALL is an operator in SQL statements which is used to combine results of two SELECT statements.

UNION: It is used to select distinct values from two tables.
UNION ALL: It is used to select all records(even duplicate) from two tables.

Can check this also for more information: <a href="https://www.w3schools.com/sql/sql_union.asp" target="_blank" rel="nofollow noopener noreferrer">SQL UNION Operator</a>
ya, perfectly right.
next question from computer networks....

2. Which of the following is done in the physical layer of the ATM network?

(a) Cell multiplexing and demultiplexing

(b) Generic flow control

(c) Transmission frame generation/ recovery

(d) Monitoring of the user information field for bit errors and possible corrective actions

P.S. - I was thinking to ask question from toughest subject automata, anyways, next question will be from there,. Be Prepared
shalini_goel14

@shalini-goel14-ASmC2J • Jun 17, 2009

Qn : Which of the following is done in the physical layer of the ATM network?

(a) Cell multiplexing and demultiplexing

(b) Generic flow control

(c) Transmission frame generation/ recovery

(d) Monitoring of the user information field for bit errors and possible corrective actions

Ans is a) Cell Multiplexing and demultiplexing ? ATM network Physical layer is similar to OSI (Open System Interconnection ) Reference Model ?