Oracle Interview Questions and Answers
101. HOW
PL/SQL IS DIFFERENT FROM SQL?
Ans: SQL is
non-procedural language whereas PL/SQL is procedural
language
that includes features and design of programming language.
102. WHAT
IS ARCHITECTURE OF PL/SQL?
Ans: Give picture & Explain
103. WHAT
IS A PL
Ans: DECLARE
<declarations>
BEGIN
<Exececutable Statements>
EXCEPTION
<Exception Handler(s)>
END;
104. WHAT
ARE DIFFERENT TYPES OF PL/SQL BLOCKS?
Ans:
DECLARE BLOCK: In this block all the declarations of the variable
used in the
program is made. If no variables are used this block will become optional.
BEGIN BLOCK: In this block all the
executable statements are
placed. This block is Mandatory.
EXCEPTION BLOCK: In this block all
the exceptions are handled.
This block is also very
optional.
END: Every begin must be ended with
this END; statement.
105. WHAT ARE COMPOSITE DATA TYPES?
Ans:
Records, Tables are two Composite data types.
106. WHAT
IS SCOPE OF A VARIABLE IN PL
Ans: The
visuability and accessibility of a variable within the
block(s) is
called scope of a variable.
107. WHAT
IS A NESTED BLOCK?
Ans: A
block within a block is called Nested Block.
108. WHAT
IS A PL
Ans: The PL/SQL engine accepts any valid PL/SQL
block as input, executes the procedural part of the statements and sends the
SQL statements to the SQL statement executor in the Oracle server.
109. WHAT
IS DEFAULT VALUE FOR A NUMERIC PL
Ans: NULL
110. WHAT
IS DIFFERENCE BETWEEN SIMPLE LOOP AND A FOR
LOOP?
Ans: Simple
requires declaration of variables used in it and exit
condition
but For Loop doesn’t require this.
111. WHAT
IS A CURSOR? STEPS TO USE A CURSOR?
Ans: Cursor
is Private SQL area in PL/SQL.
Declare the Cursor,
Open the Cursor,
Fetch values from SQL into the local
Variables,
Close the Cursor.
112. HOW
MANY TYPES OF CURSORS ARE SUPPORTED BY ORACLE?
Ans: There are two types of cursors namely
Implicit Cursor, Explicit Cursor.
113. WHAT
IS A CURSOR FOR LOOP ?
Ans: Cursor
For Loop is shortcut process for Explicit Cursors because
the Cursor
is Open, Rows are fetched once for each iteration and the cursor is closed
automatically when all the rows have been processed.
114. WHAT
ARE CURSOR ATTRIBUTES?
Ans: %Found
%NotFound
%IsOpen
%RowCount are the cursor attributes.
115. WHAT
IS USE OF CURSOR WITH "FOR UPDATE OF" CLAUSE?
Ans: This
Clause stop accessing of other users on the particular
columns
used by the cursor until the COMMIT is issued.
116. WHAT
IS AN EXCEPTION? HOW IT IS DIFFERENT FROM ERROR?
Ans:
Whenever an error occurs Exception raises. Error is a bug whereas the Exception
is a warning or error condition.
117. NAME
SOME BUILT-IN EXCEPTIONS?
Ans: Too_Many_Rows,
No_Data_Found, Zero_Divide, Not_Logged_On
Storage_Error, Value_Error etc.
118. HOW TO
CREATE A USER-DEFINED EXCEPTION?
Ans:
User-Defined Exception is created as follows:
DECLARE
<exception name> EXCEPTION;
- - - - - - - - - ;
-
- - - - - - - -;
BEGIN
-
- - - - - - - -;
-
- - - - - - - -;
RAISE <exception name>;
EXCEPTION
WHEN <exception name> THEN
-
- - - - - - - -;
-
- - - - - - - -;
END;
119. WHAT
IS "OTHERS" EXCEPTION?
Ans: It is
used to along with one or more exception handlers.
This will handle all the errors not
already handled in the block.
120. WHAT
IS SCOPE OF EXCEPTION HANDLING IN NESTED BLOCKS?
Ans:
Exception scope will be with in that block in which exception handler is
written.
121. WHAT
IS A SUB-PROGRAM?
Ans: A
SUBPROGRAM IS A PL/SQL BLOCK, WHICH WILL BE INVOKED BY TAKING
PARAMATERS.
122. WHAT
ARE DIFFERENT TYPES OF SUB-PROGRAMS?
Ans: THEY R
TWO TYPES: 1) PROCEDURE 2) FUNCION.
123. HOW A
PROCEDURE IS DIFFERENT FROM A FUNCTION?
Ans:
Function has return key word and returns a value whereas a
Procedure
doesn’t return any value.
124. WHAT
ARE TYPES OF PARAMETERS THAT CAN BE PASSED TO FUNCTION OR PROCEDURE?
Ans: IN, IN
OUT, OUT.
125. WHAT
IS "IN OUT" PARAMETER?
Ans: A
parameter, which gets value into the Procedure or Function and
takes the
value out of the Procedure or
Function
area, is called IN OUT parameter.
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