- What are the min.extents allocated
to a rollback extent ?
Answer: Two
- What are the states of a rollback
segment ? What is the difference between partly available and needs
recovery ?
Answer: The various states of a rollback
segment are :
- ONLINE
- OFFLINE
- PARTLY AVAILABLE
- NEEDS RECOVERY
- INVALID.
- What is the difference between
unique key and primary key ?
Answer: Unique key can be null; Primary key cannot be null.
- An insert statement followed by a
create table statement followed by rollback ? Will the rows be inserted ?
Answer: No.
- Can you define multiple savepoints
?
Answer: Yes.
- Can you Rollback to any savepoint
?
Answer: Yes.
- What is the maximum no.of columns
a table can have ?
Answer: 254.
- What is the significance of the
& and && operators in PL SQL ?
Answer: The & operator means that the PL
SQL block requires user input for a variable.
The && operator means that the value of this variable should be the same as inputted by the user previously for this same variable
The && operator means that the value of this variable should be the same as inputted by the user previously for this same variable
59. Can you
pass a parameter to a cursor ?
Answer: Explicit cursors can take parameters, as the
example below shows.A cursor parameter can appear in a query wherever a
constant can appear.
CURSOR c1 (median IN NUMBER) IS
SELECT job, ename FROM emp WHERE sal > median;
SELECT job, ename FROM emp WHERE sal > median;
- What are the various types of
RollBack Segments ?
Answer: The types of Rollback sagments are as
follows :
- Public Available to all instances
- Private Available to specific
instance
- Can you use %RowCount as a
parameter to a cursor ?
Answer: Yes
- Is the query below allowed :
Select sal, ename Into x From emp Where ename = 'KING' (Where x is a record of Number(4) and Char(15))
Answer: Yes
- Is the assignment given below
allowed :
ABC = PQR (Where ABC and PQR are records)
Answer: Yes
- Is this for loop allowed :
For x in &Start..&End Loop
Answer: Yes
- How many rows will the following
SQL return :
Select * from emp Where rownum < 10;
Answer: 9 rows
- How many rows will the following
SQL return :
Select * from emp Where rownum = 10;
Answer: No rows
- Which symbol preceeds the path to the
table in
the remote database ?
Answer: @
- Are views automatically updated
when base tables are updated ?
Answer: Yes
- Can a trigger written for a view ?
Answer: No
- If all the values from a cursor
have been fetched and another fetch is issued, the output will be : error,
last record or first record ?
Answer: Last Record
- A table has the following data :
[[5, Null, 10]].What will the average function return ?
Answer: 7.5
- Is Sysdate a system variable or a
system function?
Answer: System Function
- Consider a sequence whose currval
is 1 and gets incremented by 1 by using the nextval reference we get the
next number 2.Suppose at this point we issue an rollback and again issue a
nextval.What will the output be ?
Answer: 3
- Definition of relational DataBase
by Dr.Codd (IBM)?
Answer: A Relational Database is a database
where all data visible to the user is organized strictly as tables of data
values and where all database operations work on these tables.
- What is Multi Threaded Server
(MTA) ?
Answer: In a Single Threaded Architecture (or
a dedicated server configuration) the database manager creates a separate process for each database
user.But in MTA the database manager can assign multiple users (multiple user processes) to a single dispatcher (server process), a controlling process
that queues request for work thus reducing the databases memory requirement and
resources.
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