1-PLSQL Interview 3680

8/3/2019 1-PLSQL Interview 3680

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A FUNCTION is always returns a value using the return statement.

A PROCEDURE may return one or more values through parameters or may not return at all.

A function can be called from sql statements and queries while procedure can be called in abegin end block only.

Posted by: Jyoti

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In case of function,it must have

return type.

In case of procedure,it may or may n't have return type.

In case of function, only it takes IN parametersIN case of procedure

only it take IN,OUT,INOUT parameters..

Posted by: sudipta das

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A function always return a values while procedure can return one or more values through

Parameters.

A function can call directly by sql statement like select func_name from dual while procedure

cannot.

Posted by: Madhavi

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A FUNCTION always returns a value using the return statement.

And a FUNCTION can also use OUT parameter to return a value. But Return statment must

be there.

A PROCEDURE may return one or more values through parameters or may not return at all.

A function can be called from sql stmt and pl/sql stmt.

A procedure can be called within pl/sql stmt.

Page 1 of 5What is difference between a PROCEDURE & FUNCTION ?

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In case of function,it must have

return type.

In case of procedure, it don't need return keyword.

Posted by: RISHI RAW AT

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Functions and Procedures both can return values using OUT parameter.

But Functions has return clause to return value and Procedures does not have return

statement.

Functions can be used in the sql statement and can be used as the part of the expression butProcedures can't be used.

Posted by: Sanjay Patel

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Function can have both IN and OUT parameter.

Procedure cannot have return type but may return value through OUT parameter.

Posted by: Always Learner

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FUNCTION:

-It must have return type.

-It mainly used for calculation purpose.-It is part of PL/SQL block.(that is return value to block for exection of remaining code)

PROCEDURE:-It may or may not return value.

-It is mainly to perform a task.

-It is a complete PL/SQL block.

-It is used to perform DML operation.




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Posted by: Bharadwaj

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procedure is called as part of a statement..function is called as part of an expression.

There are some purity level for a function..procedure dont have such restrictions.

Posted by: Bikash

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We use function when we wnt to compute or calculate , where as procedure use for an action

Posted by: shashank gautam

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Difference Between Function and Procedure

1.Function get terminated if error occure while Procedure continue.

2. Function compiled every time on calling but Procedure compiled one time and stored in

compiled format for furthur use.

Posted by: Md Raquib Alam

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1) Function has to Return One Value. Howecer procedure may or may not return any

values.we can return the values via procedure using OUT/IN OUT varaibles.

2)Unlike Procedures We can call function in a Select statement. Exception being we can't use

those functions in select which has OUT varaibles.

3) We can call functions during declaration itself. e.g

declarex number := func();

-----

that is all i know.

Posted by: Jaidev Thakur




4/40

Contact Jaidev Thakur

Functions

Compute some value

Should return a value

It must return only one value

Not possible to use OUT and IN OUT parameters, only IN parameter is allowed.

We can able to call functions in SELECT statement

Posted by: priya

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Functions

Compute some value

Should return a value

It must return only one value

Not possible to use OUT and IN OUT parameters, only IN parameter is allowed.

We can able to call functions in SELECT statement

Procedures

Do some actions

May return a value or may not

Possible to return more than one value

Possible to use IN, OUT and IN OUT parameters

We cannot able to call in SELECT statement

Posted by: priya

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5/40

function is a collection of sql and plsql statments

in function we can assign the return type dataype

in procedure we can not assign the return type datatype

with using function we can return only one output.

wih using procedure we can return multiple output using parameters.in function whenever declaring a variable it's type of in parameter

in procedure variable type is in inout out

Posted by: abhay

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Procedures:

1. Execute as a PL/SQL statement.

2. Do not contain RETURN clause in the header.

3. Can return none, one, or many values.

4. Can contain a RETURN statement.

Function:

1. Invoke as part of an expression

2. Must contain a RETURN clause in the header3. Must return a single value

4. Must contain at least one RETURN




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Raise_application_error is a procedure of package DBMS_STANDARD which allows to issue

an user_defined error messages from stored sub-program or database

trigger.

RAISE_APPLICATION_ERROR is a

procedure of package DBMS which

allows to issue user_defined errormessage.


Contact sudipta das

The RAISE_APPLICATION_ERROR is a procedure defined by Oracle that allows the developerto raise an exception and associate an error number and message with the procedure other

than just Oracle errors.

Posted by: Moumita Nandi

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It is Its a STANDARD procedure to communicate with a pre defined exception interactively by

returning a nonstandard error code and error message.

error_number : between -20000 to -20999

message : 2048 bytes

This can be used in both execution and exception setion;

Ex: 1 :

.....BEGIN

...

delete from employeeswhere manager_id = v_mgr;

if SQL%NOTFOUND then

RAISE_APPLICATION_ERROR(-20020,'This is not a valid manager');end if;

....

---------------------------

ex:2 :

......

EXCEPTION

when NO_DATA_FOUND then

Page 1 of 2What is Raise_application_error ?



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RAISE_APPLICATION_ERROR(-20201,'manager is not a valid employee');

END;

Page 2 of 2What is Raise_application_error ?



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User_objects, User_Source and User_error.

user_source,user_objects

Posted by: madhavi

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characteristics of DB objects are stored in data dictionary. Which can be accessed by Data

dict. views like (user/all/DBA_objects/source).

Posted by: pankaj

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user_source,user_objects

Posted by: suvrat

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Page 1 of 1Name the tables where characteristics of Package, procedure and functions are stored ?



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Stored procedures are sub programs stored in the database and can be called & execute

multiple times where in an application procedure is the one being used for a particular

application same is the way for function

Stored Procedure/Function is a compiled database object, which is used for fast response

from Oracle Engine.Difference is Stored Procedure must return multiple value and function

must return single value .

Posted by: Himanshu Kumar Tripathi

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Procedure:-

Execute as a PL/SQLstatement,No RETURN clause in

the header,Can return none, one,

or many values,Can contain a RETURNstatement

Function:-Invoke as part of an

expression,Must contain a RETURNclause in the header,Must return a single value,Must contain at least one RETURN statement

Posted by: Dev

Contact Dev

Stored procedures are sub programs stored in the database and can be called & executemultiple times where in an application procedure is the one being used for a particular

application same is the way for function

Stored Procedure/Function is a compiled database object, which is used for fast response

from Oracle Engine.Difference is Stored Procedure must return multiple value and function

must return single value .

Posted by: kiran

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The basic difference between function and procedure is that a procedure can never be used

in a sql statement while a function can be used

Page 1 of 2What is difference between stored procedures and application procedures,stored function ...



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Posted by: paritosh

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Difference between Stored Procedure and Application Procedure:

Stored Procedure is a named PLSQL block that will be compiled and used for further use. If

maintained across Servers, they can be used for different applications and Users. ApplicationProcedures are the one which will be used for local apps, this can be called local block of

code. Apart from technical characteristics, same will apply to the differences between Stored

Functions and Application Functions.Difference between Procedures and Functions:

a. Functions can be used in a select statement where as procedures cannot

b. Procedure takes both input and output parameters but Functions takes only inputparameters

c. Functions cannot return values of type text, ntext, image & timestamps where as

procedures can

d. Functions can be used as user defined datatypes in create table but procedures cannot***Eg:-create table (name varchar(10),salary getsal(name))

Here getsal is a user defined function which returns a salary type, when table is created no

storage is allotted for salary type, and getsal function is also not executed, But when we are

fetching some values from this table, getsal function get?s executed and the return

Type is returned as the result set.

Page 2 of 2What is difference between stored procedures and application procedures,stored function ...



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Implicit Cursor are declared and used by the oracle internally. whereas the explicit cursors are

declared and used by the user. more over implicitly cursors are no need to declare oracle

creates and process and closes autometically. the explicit cursor should be declared and

closed by the user.

Implict cursor can be used to handle single record (i.e) the select query used should not

yield more than one row.if u have handle more than one record then Explict cursor should be used.

Posted by: Dinesh

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It is not mandatory that when the query retrieves more than one record then explicit cursorshould be used. If the number of records is less than 100 then implicit cursor should be

used.

e.g.set serverout on;

begin

for i in (select * from emp) loopdbms_output.put_line(i.empno);

end loop;

end;

/

Posted by: Sukhamoy

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Cursor: It is automatically created by oracle for all sql dml statements including the query thatreturns one row.

Explicit cursor: These are created and managed by the user.And used for multi row selectstatement.

Posted by: josu

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Implicit cursors are oracle created and used internally by oracle,the only implicit cursor is sql.

Page 1 of 2State the difference between implicit and explicit cursor's.



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Explicit cursors are user created cursors.

Posted by: Ashish

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Cursors are used for the purpose of storing the intermediate results when executing a SQL

Query or a block of code...

Implicit Cursors are by default declared by ORacle itself and hence there is no scope of

storing resultset with more than one record where as Explicit Cursors are declared by the

User and hence can define the parameters with measure to store the no of records.

Page 2 of 2State the difference between implicit and explicit cursor's.



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CREATE OR REPLACE PROCEDURE ddl_create_proc (p_table_name IN VARCHAR2)

AS

l_stmt VARCHAR2(200);

BEGIN

DBMS_OUTPUT.put_line('STARTING ');

l_stmt := 'create table '|| p_table_name || ' as (select * from emp )';

execute IMMEDIATE l_stmt;

DBMS_OUTPUT.put_line('end ');

EXCEPTION

WHEN OTHERS THEN

DBMS_OUTPUT.put_line('exception '||SQLERRM || 'message'||sqlcode);

END;

We can create table in procedure as explained in above case. but we can't create or perform

any DDL in functions.

Posted by: Vinod Pandit

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the above given answer is correct.

but we can also create or perform any ddl in functions.

I have tested myself

Posted by: Mike

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we can create a table through pl/sql block with dbms_sql package and execute immediate

statement.

CREATE OR REPLACE PROCEDURE PROC_CREATE_NEW_TABLE(STMT VARCHAR2)

IS

Page 1 of 2How we can create a table in PL/SQL block. insert records into it??? is it possible by som...



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AUTHID CURRENT_USER

BEGIN

EXECUTE IMMEDIATE STMT;

END;

here AUTHID CURRENT_USER is used to create a table under current user privileges.through this procedure we can add our own fields of a table on run time,even it is not

depended on structure of an existing table.

Insertion record into the table, because it is DML operation so we can easily create aprocedure with simple statements or execute immediate statement.

Page 2 of 2How we can create a table in PL/SQL block. insert records into it??? is it possible by som...



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WHERE CURRENT OF clause in an UPDATE,DELETE statement refers to the latest row fetched

from a cursor. DatabaseTriggers

Where CURRENT OF clause meanscursor

points to present row of

the cursor


Contact sudipta das

WHERE CURRENT OF clause in an UPDATE,DELETE statement refers to the latest row fetched

from a cursor.

Posted by: Alagappan A M

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This clause use for update & delete most resent row with out help of ROWID and befour

update lock the particular row in the base table.FOR UPDATE clause is manditory for this

clause.

Posted by: siva kumar

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Take an example, Cursor is

Select * from EMP;and in cursor we write

Update Emp set sal = sal + 100;

that means the fetching loops will execute as many times as rows returned by the cursor and

the update will also be done for the same number of times.Now suppose, If we put a where clause in the update statement, then the result would also

not be predictable.

In the third case, we use the WHERE CURRENT OF clause in the where clause, this point out

to the current row returned by the cursor. In that case, Oracle differentiate all the rows on

the basis of RowID. But what happens if someone changes one row in the table.....that

means the rowid would be changed. So we have to manually lock all the rows of that table

by writing the FOR UPDATE/DELETE clause.

So In case of WHERE CURRENT OF clause, we should use the FOR UPDATE/DELETE clause

Page 1 of 3Explain the usage of WHERE CURRENT OF clause in cursors ?



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also. This is known as the Pessimistic/Manual Locking and this the major difference between

the Implicit Cursors and Explicit Cursors.

Posted by: Sachin Nagpal

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UPDATE and DELETE statements can use a WHERE CURRENT OF clause if they reference acursor declared FOR UPDATE. This syntax indicates that the UPDATE or DELETE should

modify the current row identified by the FOR UPDATE cursor. The syntax is:

[UPDATE | DELETE ] ...

WHERE CURRENT OF cursor_name;By using WHERE CURRENT OF, you do not have to repeat

the WHERE clause in the SELECT statement. For example:

DECLARE

CURSOR wip_cur ISSELECT acct_no, enter_date FROM wip

WHERE enter_date < SYSDATE -7FOR UPDATE;

BEGIN

FOR wip_rec IN wip_curLOOP

INSERT INTO acct_log (acct_no, order_date)

VALUES (wip_rec.acct_no, wip_rec.enter_date);

DELETE FROM wip

WHERE CURRENT OF wip_cur;

END LOOP;

END;

Posted by: sallepali nagarjun reddy

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If your program has positioned the cussor on a row,u can update its data by using update

statemnet with where current clause.

Posted by: priya

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Where current of is used to delete or update the current row that is being processed in the

cursor loop.




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Posted by: karthick VenkataRaman

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WHERE CURRENT OF CLAUSE is used when referencing the current row from an explicitcursor.

this clause allows to apply updates and deletes to the row currently being addressed,without

the need to explicitly reference ROWID.

We must use the FOR UPDATE clause in the cursor query, such thay the rows are locked on

open.




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ROWID - Hexa decimal number each and every row having unique.Used in searching

ROWNUM - It is a integer number also unique for sorting Normally TOP N Analysys.

Other Psudo Column are

NEXTVAL,CURRVAL Ofsequence are some exampls

ROWID : It gives the hexadecimal string representing the address of a row.It gives the location in database where row is physically stored.

ROWNUM: It gives a sequence number in which rows are retrieved from the database.

Posted by: jyothsna

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ROWID : Every record in a database is uniquely identified by system generated value called

Rowid. It Is a 18 character hexma decimal value. These Rowid's are physically existence.

ROWNUM : It is a pseduocolumn which generates the sequence of numeric values based on

the position ofthe records in the output. These ROWNUM'S logically generated.

NEXTVAL,CURRVAL,SYSDATE,LEVEL ARE PSEDUOCOLUMNS

Posted by: Satyanarayana Reddy velagala

Page 1 of 1Explian rowid,rownum?What are the pseduocolumns we have?



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Advantage :

In pl/sql if you want perform some actions more than one records you should user these

cursors only. bye using these cursors you process the query records. you can easily move

the records and you can exit from procedure when you required by using cursor attributes.

disadvantage:

using implicit/explicit cursors are depended by sutiation. if the result set is les than 50 or

100 records it is better to go for implicit cursors. if the result set is large then you should use

exlicit cursors. other wise it will put burdon on cpu.

Disadvantage:

Each time we fetch a row from the cursor, it result a network round trip, where as a normal

select statement query make only one round trip.

Posted by: Praveen Jindal

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The guy's answer at the top ofthis page about "Cursors" is probably not wrong but sounds

wrong and it is hard to understand, it sounds like he has tried to type the answer in english

but it is shameful, his english is totally broken, it is bad. You guys at coolinterview.com

should do something about such posting to keep up the readership.

Posted by: good programmer

Contact good programmer

Advantage of cursor1.Basically cursor is a logical place or it is active set.

when a single query returns more than one rows in that case we can use the cursor. we

don't need hit the database several time. Cursoralways points the latest rows.

Disadvantage of cursor1.As such there is no disadvantage

of cursor.


Contact sudipta das

Page 1 of 2State the advantage and disadvantage of Cursor?



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Advantages:

Cursors are somewhat like Pointers of Oracle, Oracle executes a query and assign some

name to that memory location, which is known as Cursor.Cursors are used for storing data temperarorily.

Cursors are used for storing, managing and retrieving data.

Cursors stores in the RAM so the data access and retrieval is fast.

Disadvantage:

No such disadvantage. Only thing is that rather than storing data in an intermediate variable

and fetching it one by one via cursor and then processing it sequentially, we can use

Collections. By using collections, we can pass the bundle of Data at once.


Contact Sachin Nagpal

Cursors adv:

easier to retrieve a batch of records into the cursor and then perform manipulations on them

before displaying the results.

Disadvantage:

The biggest disadvantage of cursors is that they eat up you RAM. If you're retrieving a large

number of records into your cursor inside a procedure on an OLAP database, it will take a

long long time to execute that procedure. The better alternative would be to retrieve directly

from one or more table using selection criteria to eliminate records, and perform

manipulation on each record on the fly.

Posted by: HarshDeep Singh

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cursor is nothing but it's a memory area of executing sql or oracle statements.Advantage:

1. We can retrieve more than one record by one query.

2. It's use our RAM so retrieval is fast.

3. By using Collection we can retrieve the bundle of data in cursor.

Disadvantage:

No such of disadvantage of cursor. When we use cursor one thing is necessary. When I have

select only 50 or 100 rows we should use implicit cursor and when more record then weshould use Explicit cursor.

Posted by: Amit Singh

Page 2 of 2State the advantage and disadvantage of Cursor?



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InsertUpdateDelete

Before Row o.k. o.k. o.k.

After Row o.k. o.k. o.k.

Before Statement o.k. o.k. o.k.

After Statement o.k. o.k. o.k.If FOR EACH ROW clause is specified, then the trigger for each Row affected by the

statement.

If WHEN clause is specified, the trigger fires according to the returned Boolean value.

Row level trigger,Statement level trigger,Instead of trigger(created on views)

Posted by: shrinivas singh

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Baically there only 1 type of trigger which can be fired on the table. .i.e., DML TRIGGER.

There are 14 types of DML TRIGGER

But we can fire only 12 types of triggers, because remaining 2 types of triggers fire on View.

1. Before insert on ROW LEVEL TRIGGER

2. 1. AFTER insert on ROW LEVEL TRIGGER

3. Before insert on STATEMENT LEVEL TRIGGER

4. After insert on STATEMENT LEVEL TRIGGER

5. Before update on ROW LEVEL TRIGGER

6. After update on ROW LEVEL TRIGGER

7. Before update on STATEMENT LEVEL TRIGGER.

8. After update on STATEMENT LEVEL TRIGGER.

9. Before Delete on STATEMENT LEVEL TRIGGER.

10 After Delete on STATEMENT LEVEL TRIGGER.

11. Before Delete on ROW LEVEL TRIGGER.

12 After Delete on ROW LEVEL TRIGGER


Contact RISHI RAWAT

Page 1 of 1How many types of database triggers can be specified on a table ? What are they ?



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Currently, cursor variables are subject to the following restrictions:You cannot declare cursor

variables in a package spec. For example, the following declaration is not allowed:CREATE

PACKAGE emp_stuff AS TYPE EmpCurTyp IS REF CURSOR RETURN emp%ROWTYPE; emp_cv

EmpCurTyp; -- not allowedEND emp_stuff;You cannot pass cursor variables to a procedure

that is called through a database link.If you pass a host cursor variable to PL/SQL, youcannot fetch from it on the server side unless you also open it there on the same server

call.You cannot use comparison operators to test cursor variables for equality, inequality, or

nullity.You cannot assign nulls to a cursor variable.Database columns cannot store the valuesof cursor variables. There is no equivalent type to use in a CREATE TABLE statement.You

cannot store cursor variables in an associative array, nested table, or varray.Cursors and

cursor variables are not interoperable; that is, you cannot use one where the other is

expected. For example, you cannot reference a cursor variable in a cursor FOR loop

u cannot declare cursor in package specification

not allowed when using db links

cannot use comparison operators

cannot assign NULL

cursor's values cannot be stored in table columns

cannot be used with associative array, nested tables and varray

cannot be use one where the other is expected

cannot reference a cursor variable in cursor FOR LOOP

cannot direclty goto any columns

Posted by: NA

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Page 1 of 1What are the Restrictions on Cursor Variables?



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we cannot commit inside a trigger.

As we all know that when a dml is complete one can issue a commit.

A trigger if created is fired before the dml completes.

so we cannot commit intermediately.

Posted by: kapil sawant

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As workaround, one can use autonomous transactions. Autonomous transactions execute

separate from the current transaction.

Unlike regular triggers, autonomous triggers can contain COMMIT and ROLLBACK statements

Posted by: Jobs

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Having Commit / Rollback inside a trigger defeats the standard of whole transaction's

commit / rollback al together. Once trigger execution is complete then only a transaction canbe said as complete and then only commit should take place.

If we still want to carry out some action which should be initiated from trigger but should be

commited irrespective of trigger completion / failure we can have AUTONOMUS

TRANSACTION. Inside Automomus transaction block we can have Commit and it will act as

actual commit.

Specific queries a most welcome.

D.

Posted by: Durgesh

Contact Durgesh

We can't perform two action at a time in a trigger i.e trigger action and coomit/rollback/save

point.Otherwise deadlock situation occur as a result we will get a error in the transaction.

Posted by: Swagatika Sarangi

Page 1 of 1Can Commit,Rollback ,Savepoint be used in Database Triggers?If yes than HOW? If no ...



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Trigger is an event driven PL/SQL block. Event may be any DML transaction.

Cursor is a stored select statement for that current session. It will not be stored in the

database, it is a logical component.

Function is a set of PL/SQL statements or a PL/SQL block, which performs an operation and

must return a value.

Posted by: Girish P

Contact Girish P

Cursorcursor is a private sql work area.

Every sql statement executed

by oracle server has an individual

cursor associated with it.Cursor are two types

1.Implicit cursor

2.Explicit cursor

Implicit cursor: Implicit cursors

are declared by pl/sql implicitly

at the time ofDML statement and select statement in pl/sql including queries that returns

single row.cursor have four attributes

1. SQL%ROWCOUNT

2. SQL%ISOPEN3. SQL%NOTFOUND

4. SQL%FOUND

SQL%ROWCOUNT-Basically it returnsnumber.

means number of rows

affected by present sql statement.

SQL%ISOPEN-Always evalutes false

because implicit cursor automatically closed after execution of sql statement.SQL%FOUND-Always evalutes true

because one or more rows are affected by recent sql statement

SQL%NOTFOUND-Always evalutes true when no rows are affected bypresent sql statement.

example of explicit cursor

DECLAREv_empno employees.employee_id%TYPE;

v_name employees.last_name%TYPE;CURSOR emp_cur IS

SELECT employee_id,last_name

FROM employees

BEGIN

OPEN emp_cur;LOOP

Page 1 of 3What is trigger,cursor,functions in pl-sql and we need sample programs about it?



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FETCH emp_cur INTO v_empno,v_name ;

EXIT WHEN emp_cur%ROWCOUNT>10 OR

emp_cur%NOTFOUND;

DBMS_OUTPUT.PUT_LINE('employee_id:'||TO_CHAR(v_empno) ||

'employee_name:'||'v_name');

END LOOP;

CLOSE emp_cur;END;

Trigger:-Trigger is pl/sql block orprocedure that is associated with table,view,schema and database.

Execute immidiately when particular event take place.

there are two types of trigger

1.Application trigger:fires automatically when event occurs with particular application.

2.Database trigger:Fires when

data such as DML oparation occured at that time.

DML triggers are two types

1.Statementlevel trigger2.Rowlevel trigger

statement level trigger-statement level trigger means trigger bodyexecute once for the triggering event.this is default.A statement level trigger fire once even

no rows are affected at all.

Row level- Trigger body executeonce for each row affected by triggering event.if no rows are

affected in that case trigger body

not executed.

trigger example

CREATE OR REPLACE TRIGGER secure_emp

BEFORE INSERT ON employees

BEGINTO_CHAR(SYSDATE,'DY')IN('SUN','SAT') OR TO_CHAR((SYSDATE,'HH24:MI')NOT BETWEEN

'08:00' AND '18:00')THENRAISE_APPLICATION_ERROR(-20253,'u may insert employee information at business hrs');

END;

Posted by: Sudipta Das

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Cursor:

cursor is temporary work area in

pl/sql.

Type of cusor:

1.Implict Cursor

2.Explicit Cursor3.Cursor for loop

4.Cursor With Parametter




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5.Cursor for Update

6.Ref Cursor

Curosr Attributes:

%foud%notfound

%rowCount

%isopen

Trigger:

Trigger is asscoiated with table or database event(when a table affect like dml operation that

time occurs fire)

Types of Trigger:

we can write 12 types trigger

Posted by: raja

Contact raja

Trigger is a stored procedure that invokes automatically when the event occurs.We can write 12 types of triggers on table and 15 types of triggers on views.

Cursor pointer or handler to the context area . 2 types of cursors are there

implicit and explicit cursors.

Posted by: Aruna




27/40

Trigger is an event driven PL/SQL block. Event may be any DML transaction.

Cursor is a stored select statement for that current session. It will not be stored in the

database, it is a logical component.

Function is a set of PL/SQL statements or a PL/SQL block, which performs an operation and

must return a value.

Posted by: Girish P

Contact Girish P

Cursorcursor is a private sql work area.

Every sql statement executed

by oracle server has an individual

cursor associated with it.Cursor are two types

1.Implicit cursor

2.Explicit cursor

Implicit cursor: Implicit cursors

are declared by pl/sql implicitly

at the time ofDML statement and select statement in pl/sql including queries that returns

single row.cursor have four attributes

1. SQL%ROWCOUNT

2. SQL%ISOPEN3. SQL%NOTFOUND

4. SQL%FOUND

SQL%ROWCOUNT-Basically it returnsnumber.

means number of rows

affected by present sql statement.

SQL%ISOPEN-Always evalutes false

because implicit cursor automatically closed after execution of sql statement.SQL%FOUND-Always evalutes true

because one or more rows are affected by recent sql statement

SQL%NOTFOUND-Always evalutes true when no rows are affected bypresent sql statement.

example of explicit cursor

DECLAREv_empno employees.employee_id%TYPE;

v_name employees.last_name%TYPE;CURSOR emp_cur IS

SELECT employee_id,last_name

FROM employees

BEGIN

OPEN emp_cur;LOOP




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FETCH emp_cur INTO v_empno,v_name ;

EXIT WHEN emp_cur%ROWCOUNT>10 OR

emp_cur%NOTFOUND;

DBMS_OUTPUT.PUT_LINE('employee_id:'||TO_CHAR(v_empno) ||

'employee_name:'||'v_name');

END LOOP;

CLOSE emp_cur;END;

Trigger:-Trigger is pl/sql block orprocedure that is associated with table,view,schema and database.

Execute immidiately when particular event take place.

there are two types of trigger

1.Application trigger:fires automatically when event occurs with particular application.

2.Database trigger:Fires when

data such as DML oparation occured at that time.

DML triggers are two types

1.Statementlevel trigger2.Rowlevel trigger

statement level trigger-statement level trigger means trigger bodyexecute once for the triggering event.this is default.A statement level trigger fire once even

no rows are affected at all.

Row level- Trigger body executeonce for each row affected by triggering event.if no rows are

affected in that case trigger body

not executed.

trigger example

CREATE OR REPLACE TRIGGER secure_emp

BEFORE INSERT ON employees

BEGINTO_CHAR(SYSDATE,'DY')IN('SUN','SAT') OR TO_CHAR((SYSDATE,'HH24:MI')NOT BETWEEN

'08:00' AND '18:00')THENRAISE_APPLICATION_ERROR(-20253,'u may insert employee information at business hrs');

END;

Posted by: Sudipta Das

Contact Sudipta Das

Cursor:

cursor is temporary work area in

pl/sql.

Type of cusor:

1.Implict Cursor

2.Explicit Cursor3.Cursor for loop

4.Cursor With Parametter




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5.Cursor for Update

6.Ref Cursor

Curosr Attributes:

%foud%notfound

%rowCount

%isopen

Trigger:

Trigger is asscoiated with table or database event(when a table affect like dml operation that

time occurs fire)

Types of Trigger:

we can write 12 types trigger

Posted by: raja

Contact raja

Trigger is a stored procedure that invokes automatically when the event occurs.We can write 12 types of triggers on table and 15 types of triggers on views.

Cursor pointer or handler to the context area . 2 types of cursors are there

implicit and explicit cursors.

Posted by: Aruna




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The table columns are referred as OLD.column_name and NEW.column_name.

For triggersrelated to INSERT only NEW.column_name values only available.

For triggers related to UPDATE only OLD.column_name NEW.column_name values only

available.

For triggers related to DELETE only OLD.column_name values only available.

Two tables are: OLD and NEW.

Insert Trigger :

OLD - no value.NEW - inserted value.

UPDATE TRIGGER -OLD- old value.

NEW- new updated value.

DELETE TRIGGER -

OLD - old value.NEW - no value.


Page 1 of 1What are two virtual tables available during database trigger execution ?



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In PL/SQL ,pointer has a datatype REF X where

REF-Reference

X-class of objects

Cursor Variables has a datatype REF-CURSOR

where Cursor Varibales are like pointers which hold the memory location of some item

instead of the item itself.

Posted by: shikha srivastava

Contact shikha srivastava

Ref Cursor is cursor variable. It is a pointer to a result set. It is useful in scenarios when

result set is created in one program and the processing of the same in some other, might bewritten in different language, e.g. firing the select is done in PL/SQL and the processing will

be done in Java.

Posted by: Sukhamoy

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Its a run time query binding with the cursor variable. Normal cursors are static cursors becaz

they get acquited of query at the compile time.

Posted by: Rup

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Ref cursors are used when we want to use the cursor which is not bound to a specific query.Cursor variables can be tied to many such type of compatible queries.

Posted by: Jyothsna

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Ref cursor is user defined type.Ref cursor allows any type of query for the cursor.Ref cursoris a global declaration of the cursor.Ref cursor is re-usable.

Ref cursor reduces the number of declarations of the cursor in the entire plsql program.Ref

cursor is either static or dynamic.

Page 1 of 2What is ref cursor?



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Posted by: jaali

Contact jaali

Ref cursor is a cursor variable is used to pass the result sets between sub programs.

Ref cursors are 2 types

1.weak Ref cursor and2. Strong Ref cursor

If a ref cursor should not return any value then it is called as weak ref cursor and if a cursorreturns the value then it is strong ref cursor.

weak ref cursors are more flexible because you can associate a weakly typed cursor varibleto any query

Posted by: Aruna

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Ref cursor is a dynamic cursor with which we can change our query contents at run time.once it is defined thereafter we can declare a cursor variable of that(ref cursor) data type

and write any number of type compatible query against this cursor variable.

Posted by: Ravindra Kumar Ray

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Page 2 of 2What is ref cursor?



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% ROWTYPE is to be used whenever query returns a entire row of a table or view.

TYPE rec RECORD is to be used whenever query returns columns of different

table or views and variables.

E.g. TYPE r_emp is RECORD (eno emp.empno% type,ename emp ename %type

);e_rec emp% ROWTYPE

cursor c1 is select empno,deptno from emp;

e_rec c1 %ROWTYPE.

Page 1 of 1What is difference between % ROWTYPE and TYPE RECORD ?



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You can use DBMS_OUTPUT oracle supplied package or DBMS_DEBUG pasckage.

Posted by: Nasir Ali

Contact Nasir Ali

put a dbms output_putline statment which will dislapay that your procedure is executing

successfully up to which stage.

Posted by: sanjay

Contact sanjay

By using the sql developer tools and in that use breakpoints (the location from which u want todebug and execute line by line at the same time you will notice the current value of the

executed statement below in another windows) and don't forgot to enable the

dbms_output ).

In this way you can do the same things

Posted by: RAJESH KUMAR

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We can also do line by line execution using tools such as Pl/ SQL Developer, Toad etc

Posted by: Amit Gupta

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if you want to tune a package then you can use dbms_profiler. if you want to debug use

dbms_debug procedure.

Thanks,

Sudipta

Posted by: Sudipta

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Page 1 of 2How to debug the procedure ?



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ALTER PROCEDURE procedurename

DEBUG;

OR

ALTER PROCEDURE procedurenamePLSQL_DEBUG=TRUE

Posted by: priya

Page 2 of 2How to debug the procedure ?



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By declaring this cursor we can updatethe table emp through z,means wo not need to write

table name for updation,it may be only by "z".

selecting in FOR UPDATE mode locks the result set of rows in update mode, which meansthat row cannot be updated or deleted until a commit or rollback is issued which will release

the row(s).

Posted by: Ash

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You will get an error. Since, the commit/rollback closes the cursor and release the lock if you

use for update of, so trying to fetch out of a closed cursor will raise an error.

Posted by: Nattu

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The procedure executes successfully.COMMIT will not close the cursor.

declare

b boolean;

cursor c is select * from emp for update;rec c%rowtype;

begin

open c;fetch c into rec;

dbms_output.put_line('NAME is'||rec.ename);

commit;if c%isopen then

dbms_output.put_line('Cursor is not closed '||c%rowcount);

end if;

fetch c into rec;

dbms_output.put_line('NAME is'||rec.ename);end;

O/P

****

NAME isSMITH

Cursor is not closed 1

NAME isALLEN

Page 1 of 3What will the Output for this Coding? Declare Cursor c1 is select * from emp FORUPDA...



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Posted by: Srikri

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This coding get sucessful but after completed this query we con't delete or update to the EMP

table because of we used FOR UPDATE clause, they explictly locked the entire row still not

relese.

Posted by: siva kumar

Contact siva kumar

The cursor will execute for first record and then for second record it will raise exception.

Because the ROWS which were locked by FOR UPDATE clause, now been released bycommit.


Contact RISHI RAWAT

The following error will occur as there is a space between IN TO.

ERROR at line 8:

ORA-06550: line 8, column 11:PLS-00103: Encountered the symbol "IN" when expecting one of the following:

. into bulk

Posted by: Chella

Contact Chella

It will ORA:01002 fetch out of sequence error

If the cursor has been opened with the FOR UPDATE clause, fetching after a COMMIT willreturn the error.

Posted by: kalam

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If the table which we are using in the cursor is empty then procedure will run successfully.

But if table contains rows in it, it will give error as " fetch out of sequence"

Posted by: Trupti Salvi




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Function is called as part of an expression.

sal := calculate_sal ('a822');

procedure is called as a PL/SQL statement

calculate_bonus ('A822');

Function can be called from SQL query + explicitly as well

e.g 1)select empno,salary,fn_comm(salary)from employee;

2)commision=fn_comm(salary);

Procedure can be called from begin-end clause.

e.g.

Begin(

proc_comm(salary);

)end

Posted by: Hirenkumar

Contact Hirenkumar

Function:Example

Select get_name(Emp_id) from dual.

Procedure:

Example

BeginProcess_employee(EMP_ID);

end;

Posted by: nikhil

Page 1 of 1Explain how procedures and functions are called in a PL/SQL block ?



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In the standard package.

Procedures, Functions & Packages ;

It stores in standard_package.

Posted by: Amit Singh

Contact Amit Singh

Page 1 of 1Where the Pre_defined_exceptions are stored ?

1-PLSQL Interview 3680

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