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July 25, 2017

7/25/2017 02:28:00 AM
Oracle SQL Interview Questions
Oracle SQL : Interview Questions


1)What is difference between Rename and Alias 

Rename is a permanent name given to a table or column whereas Alias is a temporary 
name given to a table or column which do not exist once the  SQL statement is 
executed. 
  
2)How you will avoid your query from using indexes 
  
SELECT * FROM emp 
Where emp_no+' '=12345; 

3).  Difference between NO DATA FOUND and %NOTFOUND 
  
NO DATA FOUND is an exception raised only for the SELECT....INTO statements 
when the where clause of the querydoes not  match any rows. 
When the where clause of the explicit cursor does not match any rows the %NOTFOUND attribute is set to TRUE instead

4)What should be the return type for a cursor variable.Can we use a scalar data type as return type. 
The return type for a cursor must be a record type.
It can be declared explicitly as a user-defined or %ROWTYPE  can be used. eg  TYPE  t_studentsref  IS  REF CURSOR  RETURN  students%ROWTYPE 

5)What is difference between a formal and an actual parameter 
  
The variables declared in the procedure and which are passed, as arguments are called 
 actual, the parameters in the procedure declaration. 
Actual parameters contain the  values that are passed to a procedure and receive results. 
Formal parameters are the  placeholders for the values of actual parameters 


 
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