Databases - Upwork

Question: What will happen if you query the emp table as shown below: select empno, DISTINCT ename, Salary from emp;
A
EMPNO, unique value of ENAME and then SALARY are displayed

B
EMPNO, unique value ENAME and unique value of SALARY are displayed

C
DISTINCT is not a valid keyword in SQL

D
No values will be displayed because the statement will return an error

Note: Not available
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Question: What is a rollback of transactions normally used for?
A
Recover from the transaction failure

B
Update the transaction

C
Retrieve old records

D
None of the above

Note: Not available
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Question: The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER (12) SEMESTER_END DATE GPA NUMBER (4) Which of the following statements finds the highest Grade Point Average (GPA) per semester?
A
SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL

B
SELECT (gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL

C
SELECT MAX(gpa) FROM student_grades WHERE gpa IS NOT NULL GROUP BY semester_end

D
SELECT MAX(gpa) GROUP BY semester_end WHERE gpa IS NOT NULL FROM student_grades

E
SELECT MAX(gpa) FROM student_grades GROUP BY semester_end WHERE gpa IS NOT NULL

Note: Not available
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Question: Which of the following is not a single value function?
A
Round

B
Floor

C
Avg

D
Sqrt

E
Tan

Note: Not available
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Question: An RDBMS performs the following steps: 1)It calculates the results of the group functions of each group 2)It groups those rows together based on the group by clause 3)It orders the groups based on the results of the group functions in the order by clause 4)It chooses and eliminates groups based on the having clause 5)It chooses rows based on the where clause Arrange the above steps in the correct order of execution:
A
4,3,5,1,2

B
4,5,3,2,1

C
5,2,1,4,3

D
5,2,3,4,1

E
2,3,1,4,5

F
2,3,1,5,4

G
1,2,3,4,5

H
3,2,1,4,5

Note: Not available
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Question: Data validation can be implemented at the data definition stage through:
A
Check constraints with specified values

B
Referential constraints, by creating foreign keys for another table

C
Default value of column

D
Not Null constraint

Note: Not available
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Question: What clause should be used to display the rows of a table in ascending order of a particular column?
A
Where

B
Order By

C
Group By

D
Having

E
First Group By and then Having

F
Like

G
Between

Note: Not available
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Question: What is the error in the following query if the Students table contains several records? select name from students where name = (select name from students order by name);
A
= should be replaced by in operator

B
Order by clause in the subquery should be preceded with a group by clause

C
Order by clause in the subquery can be used only if the where and group by clauses have been applied

D
Group by clause should be applied to the outer query

E
An order by clause is not allowed in a subquery

F
There is no error

Note: Not available
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Question: In which type of database is SQL used?
A
Hierarchical

B
Network

C
Relational

D
Object oriented

E
All of above

Note: Not available
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Question: The concept of data independence is similar to the concept of ________
A
Data type

B
Abstract data type

C
Consolidation

D
Isolation

Note: Not available
1. Report

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Question: What will happen if you query the emp table as shown below: select empno, DISTINCT ename, Salary from emp;

Question: What is a rollback of transactions normally used for?

Question: The STUDENT_GRADES table has these columns: STUDENT_ID NUMBER (12) SEMESTER_END DATE GPA NUMBER (4) Which of the following statements finds the highest Grade Point Average (GPA) per semester?

Question: Which of the following is not a single value function?

Question: Data validation can be implemented at the data definition stage through:

Question: What clause should be used to display the rows of a table in ascending order of a particular column?

Question: What is the error in the following query if the Students table contains several records? select name from students where name = (select name from students order by name);

Question: In which type of database is SQL used?

Question: The concept of data independence is similar to the concept of ________