Quick Revision

GK One-Line Question & Answer

15541+ short questions with short answers, covering every category and sub-category on the site — no long articles to scroll through. Good for a fast recap before an exam, or a few minutes of daily practice.

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DBMS → Indexes 3

If a1, a2, a3 are attributes in a relation and S is another relation, which of the following is an incorrect specification of an integrity constraint?
foreign key(a1, a2)
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With SQL, how do you select all the records from a table named “Persons” where the value of the column “FirstName” ends with an “a”?
SELECT * FROM Persons WHERE FirstName LIKE ‘%a’
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The command to remove rows from a table ‘CUSTOMER’ is __________________
DELETE FROM CUSTOMER WHERE
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DBMS → Transactions 3

What is the syntax to load data into the database? (Consider D as the database and a, b, c as datA:)
insert into D values (a, b, C:);
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With SQL, how can you return all the records from a table named “Persons” sorted descending by “FirstName”?
SELECT * FROM Persons ORDER BY FirstName DESC
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What type of join is needed when you wish to include rows that do not have matching values?
Outer join
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DBMS → Concurrency Control 3

Which of the following commands do we use to delete a relation (R) from a database?
drop table R
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With SQL, how can you return the number of not null records in the “Persons” table?
SELECT COUNT(*) FROM Persons
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What type of join is needed when you wish to return rows that do have matching values?
All of the Mentioned
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DBMS → Deadlock 3

Which of the following commands do we use to delete all the tuples from a relation (R)?
delete from R
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What does the ALTER TABLE clause do?
The SQL ALTER TABLE clause modifies a table definition by altering, adding, or deleting table columns and/or constraints
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Which of the following is one of the basic approaches for joining tables?
All of the Mentioned
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DBMS → Database Security 2

Choose the correct command to delete an attribute A from a relation R
alter table R drop A
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The UPDATE SQL clause can _____________
update more than one row at a time
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DBMS → PL/SQL 2

create table apartment(ownerID varchar (5), ownername varchar(25), floor numeric(4,0),<br>primary key (ownerID:));<br>Choose the correct option regarding the above statement
It creates a relation with three attributes ownerID, ownername, floor in which ownerID cannot be null.
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The UNION SQL clause can be used with _____________
SELECT clause only
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DBMS → Introduction to DBMS 2

What does the notnull integrity constraint do?
It ensures that all tuples have a finite value on a specified attribute
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Which SQL statement is used to return only different values?
SELECT DISTINCT
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DBMS → Database Architecture 2

Which SQL function is used to count the number of rows in a SQL query?
COUNT(*)
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Which SQL keyword is used to sort the result-set?
ORDER BY
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DBMS → Data Models 2

Which SQL keyword is used to retrieve a maximum value?
MAX
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How can you change “Hansen” into “Nilsen” in the “LastName” column in the Persons table?
UPDATE Persons SET LastName=’Nilsen’ WHERE LastName=’Hansen’
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DBMS → ER Model 2

Which of the following SQL clauses is used to DELETE tuples from a database table?
DELETE
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Which of the following command makes the updates performed by the transaction permanent in the database?
COMMIT
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DBMS → Relational Model 2

___________removes all rows from a table without logging the individual row deletions.
TRUNCATE
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Which TCL command undo all the updates performed by the SQL in the transaction?
ROLLBACK
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DBMS → Normalization 2

Which of the following is not a DDL command?
UPDATE
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SQL query to find all the cities whose humidity is 95.
SELECT city FROM weather WHERE humidity = 95
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DBMS → Functional Dependency 2

Which of the following are TCL commands?
ROLLBACK and SAVEPOINT
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SQL query to find the temperature in increasing order of all cities.
SELECT city, temperature FROM weather ORDER BY city
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DBMS → SQL Basics 2

________________ is not a category of SQL command.
SCL
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What is the meaning of LIKE ‘%0%0%’?
Feature has two 0’s in it, at any position
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DBMS → DDL Commands 2

If you don’t specify ASC or DESC after a SQL ORDER BY clause, the following is used by default ______________
ASC
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Find the names of these cities with temperature and condition whose condition is neither sunny nor cloudy.
SELECT city, temperature, condition FROM weather WHERE condition NOT IN (‘sunny’, ‘cloudy’)
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DBMS → DML Commands 2

Which of the following statement is true?
DELETE does not free the space containing the table and TRUNCATE free the space containing the table
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Find the name of those cities with temperature and condition whose condition is either sunny or cloudy but temperature must be greater than 70.
SELECT city, temperature, condition FROM weather WHERE condition = ‘sunny’ OR condition = ‘cloudy’ AND temperature > 70
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DBMS → Joins 2

What is the purpose of the SQL AS clause?
The AS SQL clause is used to change the name of a column in the result set or to assign a name to a derived column
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Find all the tuples having a temperature greater than ‘Paris’.
SELECT * FROM weather WHERE temperature > (SELECT temperature FROM weather WHERE city = ‘Paris’
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DBMS → Views 2

What does DML stand for?
Data Manipulation language
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Find all the cities with temperature, condition and humidity whose humidity is in the range of 63 to 79.
SELECT * FROM weather WHERE humidity BETWEEN 63 AND 79
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