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What is difference between "Primary key" and "Unique key"?
neha.awasthi1
- May 19th, 2011
Both primary key and unique contain unique value.1: primary key cant be nullUnique key can be null.2: Multiple column of table van be defined as unique key.Only one column can defined as primary key
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HiWhile creating a table, what is the difference between VARCHAR2(80) and VARCHAR2(80 BYTE)?
Baji Shaik
- Jun 5th, 2011
Varchar2(80) accept upto 80 characters,varchar2(80 byte) accept upto 80*8=640 characters
psingla
- Apr 28th, 2010
If system parameter NLS_LENGTH_SEMANTICS is set to defaultthen no differenceIf system parameter NLS_LENGTH_SEMANTICS is changed from default behavior BYTE to CHAR.then VARCHAR2(80) means VARCHAR...
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What is diff between strong and weak ref cursors
Baji Shaik
- Jun 5th, 2011
Strong ref cursor return value, but seek ref cursor it can't return any value
askvenki
- Jul 20th, 2007
A strong REF CURSOR type definition specifies a return type, but a weak definition does not.DECLARE TYPE EmpCurTyp IS REF ...
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Suppose thr are 10 DMLs(insert,update,delete ) in the main section of the PL/SQL block .The exception in them is handled as a whole in the exception handling section .....The error may occur in any of this DMLs ,so how can we understand that which DML has failed ??
sandeshshinde000
- Jun 4th, 2011
begin DML 1 ' ' ' ' ' DML 10exceptionwhen others thandbms_output('error at location '||dbms_utility.format_error_backtrace);e...
BakulPatel
- May 7th, 2011
To simplify Remove exception block. Oracle will show line number with error thrownOther method:beginlocation :=1; dml1 location :=2; dml2exception when others than&nb...
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What is PL/SQL table? SNO MARK ------- ------------------1 592 403 ‘A’4 60 Write a single query to I) Sorted Marks II)First mark III) replace the mark ‘A’ with 0(zero)?
NehaChanda
- May 22nd, 2009
We can not use MAX on PLSQL table. Check if it works.Create a PLSQL Table Sorted_Mark.SNO_MARK(3) := 0; - Replace ASorted in another Collection Typeselect culumn_valuebulk collect into Sorted_MARKfrom table (cast(SNO_MARK as PLSQL_DATATYPE))order by column_valueSorted_MARK(1) - First Value
samareshp
- Apr 15th, 2009
I guess the the question should be replace a with zero then sort the mark and
then show first mark, Let me know if i am wrong.
select max(mark)
from (
SELECT sno, mark
FROM (select sno, decode(mark, 'A', 0, mark) x from t) xt
ORDER BY x
)
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PL/SQL UTL_FILE Package
Which exception is used in UTL_FILE package in PL/SQL?
dinesh.smhdr
- May 19th, 2011
The package specification of UTL_FILE defines seven exceptions.INVALID_PATHINVALID_MODEINVALID_FILEHANDLEINVALID_OPERATIONREAD_ERRORWRITE_ERRORINTERNAL_ERRORNO_DATA_FOUNDVALUE_ERRORINVALID_MAXLINESIZE
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">
Talk about "Exception Handling" in PL/SQL?
krishnaindia2007
- May 7th, 2008
A warning or error condition is called an exception. An exception may raise in a pl/sql block due to designing faults, coding mistakes or hardware failure. If an exception raises in a block ...
g_sidhu
- Jan 31st, 2008
You can handle exception in two ways:– Trap it with a handler : If the exception is raised in the executable section of the block, processing branches to the corresponding exception handler...
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Can procedures have parameters
krishnaindia2007
- May 7th, 2008
Procedures Can have Parameters. But parameters is optional .i.e. we may defined procedures without parameters also.It can take three types of parametersIN , OUT and INOUT.
kanchan Patra
- Aug 7th, 2007
Yes, Procedures can have parameters.
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What is Pragma EXECPTION_INIT ? Explain the usage ?
The PRAGMA EXECPTION_INIT tells the complier to associate an exception with an oracle error. To get an error message of a specific oracle error. e.g. PRAGMA EXCEPTION_INIT (exception name, oracle error number)
g_sidhu
- Jan 31st, 2008
PRAGMA EXCEPTION_INIT statement associate the declared exception with the standard Oracle server error number. PRAGMA EXCEPTION_INIT tells the compiler to associate an exception name with an Oracle er...
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Oracle Locks Concept
Please explain How to set locktime out in Oracle.
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What is dense_rank function and it's usage ?
Teju_hassan
- Apr 20th, 2011
See the below example to understand better.select dense_rank,rank,salfrom empsorder by sal descdense_rank|rank|sal1 &...
g_sidhu
- Feb 5th, 2008
Rank Function can cause non-consecutive rankings if the tested values are the same. Whereas, the dense_rank function will always result in consecutive rankings.
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Can we call a procedure into another procedure?If yes means how you can pass the perameters for the two procedures?
debasisdas
- Apr 11th, 2011
I believe an example would be best way to explain this.The scenario is whan user passes an employee_no to be inserted into EMP table i wan that value to be check against the existing record. If the em...
Arun
- Oct 27th, 2006
Hi friendit is easyExamplecreate or replace procedure first_proc (v_name1 in varchar, v_age in number) isbegindbms_output.put_line(v_name||' is '||v_age||' years old!');end;create or replace procedure...
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Why and When would you use a package instead of standalone procedures? Which one increases performence - package or standalone procedure?
mailtonagaraja
- Mar 24th, 2011
Hi , 1) In Package we can combile all related objects into one component, whenever you refer or call any object in the package , full package will be copied to the memory , so that next ti...
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User Defined Exception Handler
Suppose a programmer creates a user defined exception handler Invalid_Number in declare block with type EXCEPTION and raise this exception in begin block. Then how will you access the user defined exception and same system defined exception (i.e Inavlid_Number)
promisinganuj
- Feb 10th, 2011
The system defined exceptions in Oracle are tied to Oracle error codes. For this case, system defined error INVALID_NUMBER is tied with error code -01722.Now, when a user defines the sa...
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PL SQL Procedure in Package
Procedure in package perfomes fastly over normal procedure, Explain.
monoranjang
- Jan 24th, 2011
A Storeprocedure is a Set of transactional SQL statements which will do some operation. Storedprocedure is precomplied . When we use sp's in our application it will reduce network traffic because ...
muraligrandhi
- Jun 8th, 2010
It's true. Procedures in the packages are faster than the stand alone procedures, because all the procedures in the package are compiled once and stored in the SGA at shared pool area. If we call the ...
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Unconstrained Loop
What is unconstrained loop?suggest some example.
vikz.pal
- Jan 23rd, 2011
Unconstrained loop means loop that can't be handled as per our will.Basic loop is a simple example of unconstrained loop - if we ignore proper exit statement in basic loop then it becomes an infin...
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DATATYPES
1-WHAT IS THE MAX LENGHT OF VARCHAR2 DATATYPE IN PL/SQL?2-WHAT IS THE USE OF UROWID?3-WHAT ARE THE SUBTYPES?GIVE ANY 2 EXAMPLE?4- WHAT IS THE GENERAL STANDARD FOR DECLARATION?
pravesh28
- Dec 27th, 2010
1... max length is 327672 rowid means row plus id actuall its psedocolmn that store the value of each rowwith the help of rowid>>> we can remove duplicate value>>> we can dispa...
muraligrandhi
- Nov 9th, 2010
1. Maximum length of a varible in PL/SQL is 32767 bytes2. The UROWID or Universal Rowid is useful for storing logical addresses of all the rows of Index-organized tables. It can store both the logical...
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How packaged procedures and functions are called from the following?
a. Stored procedure or anonymous block b. an application program such a PRC *C, PRO* COBOL c. SQL *PLUS a. PACKAGE NAME.PROCEDURE NAME (parameters); variable := PACKAGE NAME.FUNCTION NAME (arguments); EXEC SQL EXECUTE ...
shi_fu
- Nov 30th, 2010
a. procedure is called by its name:pack_name.proc_name;function is called from a expression:a=b*(function(param));b.(same as above)procedure is called by its name:pack_name.proc_name;function is calle...
g_sidhu
- Feb 17th, 2008
a. PACKAGE NAME.PROCEDURE NAME (parameters); variable := PACKAGE NAME.FUNCTION NAME (arguments); b. ...
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Bulk Data Operations
You are developing a PL/SQL block designed for bulk data operations. When attemping to store table data for multiple rows in a PL/SQL variable, which one of the following choices identifies the mechanism best suited for this task (choose one)? A. cursorB. varchar2C. recordD. table of records
rahulg5211
- Oct 25th, 2010
Table of record type is best option to perform this operation.becouse first thing pl/table has unlimited size.second thing for fetching bunch of record into pl/table,besides of INTO clause we ne...
shukla.prashant76
- Apr 28th, 2010
Answer is D. We need multiple rows on a variable so we use here Table of records .it uses just like as collection of records.Cursor is used for selecting multiple rows from stored table.Var...
PL/SQL Interview Questions
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