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BASIS ORACLE MCQ
1. In the following query, which expression is evaluated first?
SELECT id_number, (quantity – 100 / 0.15 – 35 * 20) FROM inventory
100 / 0.15
quantity – 100
35*20
0.15-35
2. Which of the following queries are legal?
SELECT deptno, count(deptno) FROM emp GROUP BY ename;
SELECT deptno, count(deptno), job FROM emp GROUP BY deptno;
SELECT deptno, avg(sal) FROM emp;
SELECT deptno, avg(sal) FROM emp GROUP BY deptno;
3. Which of the following queries displays the sum of all employee salaries for those employees not making commission, for each job, including only those sums greater than 2500?
select job, sum(sal) from emp where sum(sal) > 2500 and comm is null;
select job, sum(sal) from emp where comm is null group by job having sum(sal) > 2500;
select job, sum(sal) from emp where sum(sal) > 2500 and comm is null group by job;
select job, sum(sal) from emp group by job having sum(sal) > 2500 and comm is not null;
4. All of the following can ONLY be used with numeric data types except:
AVG
COUNT
SUM
STDDEV
5. What operator is used to prevent the error: ‘ORA-01427:single row sub query returns more than one row’ ?
Use the IN operator
Use the >= operator
Use the CAN EXIST operator
Use the = operator
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6. Which of the following SQL operations demands the use of wild cards comparisons?
IN
BETWEEN
EXISTS
LIKE
7. Indicate whether this statement is true or false. A foreign key column must contain unique values.
True
False
8. A stored procedure is only executed
implicitly
when asked explicitly
when the trigger associated with it is also invoked
none of the above
9. A database trigger is an alternative for
Stored procedure
Primary key for implementing referential integrity
Foreign key for implementing referential integrity
All of he above
10. Which of the following statements regarding primary key is false?
Primary key can not have null values
Primary key may contain duplicate values
Primary key can not be applied for multiple columns
All of the above
11. A hot backup is
taking up the backup of the database while it is still up and running
taking up the backup of the database after the user logs off
taking up the backup followed by taking cold backup
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None of the above
12. A data block is
the place where all deleted records are persisted
the largest logical storage unit ever available for any database block
the smallest logical storage unit for a database object
all of the above
13. What are the two ways to determine the structure of a table in database?
Using DESCRIBE command and dbms_metadata_get_commit package
Using METADATA command STRUCTURE commands
Using DATA_ON_DATA and STRUCTURE commands
Using DESCRIBE command and dbms_metadata_get_ddl package
14. Where would you look for errors from the database engine?
In the error log
In the alter log
In the alert log
In the recovery log
15. What TRUNCATE and DELETE commands does
To retrieve rows in a table
To remove some part of a table
To get rid of all rows in a table
To recover all the rows deleted in a table.
16. Which of the following is the root directory for oracle?
ORACLE_HOME
ORACLE_ROOT
ORACLE_BASE
ORACLE_SERVER
17. To determine the time zone under which a database was operating
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select DBTIMEZONE from root
select TIMEZONE_DB from dual
select DB_TIME_ZONE from dual
select DBTIMEZONE from dual
18. How should a many-to-many relationship be handled?
By adding an join entity table
By adding intersection entity table
By adding union entity table
By adding Cartesian entity table
19. How many triggers can be applied to a single table in Oracle?
10
12
15
16
20. Which of the following statements is true?
Implicit cursors are not named
Implicit cursors must be developed by the database developers
Explicit cursors can handle tables with only 16 rows
Explicit cursors does not occupy Oracle’s memory space
21. For referential integrity to hold, any field in a table that is declared a super key can contain only values from a parent table's primary key or a candidate key.
False
True
22. Which of the following statements hold true for a cursor?
Specify positioning at specific rows in the result set
Retrieve multiple columns based on the current result set position
Modify data in the rows at the current position in the result set
Both a and c above
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23. ____________ involves putting different rows into different tables
Horizontal partitioning
Vertical partitioning
Range partitioning
Hash partitioning24. ______________ are padded with space characters to match the specified length.
VARCHAR
VARCHAR2
CHAR
CHAR225. Using synonyms is a good way to implement location transparency.
True
False26. A cluster is a schema object that contains data from _____________ , all of which have one or more columns in common.
one table
one or more tables
two or more tables
atleast two tables
27. ____________ is an area on disk which comprises of one or more disk files
A package
A table space
A partition
Heap
28. What is the the use of Rollback Segment?
Used to roll back a transaction
Both c and d
They can be used to recover the selected tables to a consistent state in case of failures
They ensure that transactions leave the uncommitted changes unnoticed.
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