PL/SQL PL/SQL CursorsCursorsPL/SQL PL/SQL CursorsCursors

Session - IISession - II

AttributesAttributes AttributesAttributes%TYPE

%ROWTYPE

% Found

% NotFound

% RowCount

% IsOPen

%TYPE

%ROWTYPE

% Found

% NotFound

% RowCount

% IsOPen

%TYPE%TYPE%TYPE%TYPE useful when declaring variables

that refers to Database Columns

Name Varchar(15);

Name Emp.Ename%TYPE;

%ROWTYPE%ROWTYPE%ROWTYPE%ROWTYPE

Provides a record Type that represents a Row in a Table.

ENAME DESIGNATION SAL

SMITHJONES ADAMSKING

CLERK SALESMANPRSIDENT MANAGER

6000456645674500

Name Varchar(15);

Desig Varchar(15);

Salary Number(8,2);

Emp_Rec Emp%ROWTYPE;

DeclareDeclare

EmRecEmRec Emp%Rowtype; Emp%Rowtype;

BeginBegin

Select * INTO Select * INTO EmRecEmRec from emp where from emp where empno=7369;empno=7369;

Dbms_Output.put_line( Dbms_Output.put_line( emrecemrec.ename||.ename||emrecemrec.Sal.Sal););

End;End;

DeclareDeclare

EmRecEmRec Emp%Rowtype; Emp%Rowtype;

BeginBegin

Select * INTO Select * INTO EmRecEmRec from emp where from emp where empno=7369;empno=7369;

Dbms_Output.put_line( Dbms_Output.put_line( emrecemrec.ename||.ename||emrecemrec.Sal.Sal););

End;End;

CURSORSCURSORSCURSORSCURSORS

It is a Temporary Table created in the SGA of the Server.

It is a Temporary Table created in the SGA of the Server.

Two Types of Two Types of CURSORSCURSORS

Two Types of Two Types of CURSORSCURSORS

IMPLICITEXPLICIT

IMPLICIT CursorIMPLICIT CursorIMPLICIT CursorIMPLICIT Cursor

PL/SQL Implicitly declares a cursor for all SQL data Manipulation Statements, Including Queries that return only One Row

PL/SQL Implicitly declares a cursor for all SQL data Manipulation Statements, Including Queries that return only One Row

EXPLICIT CursorEXPLICIT CursorEXPLICIT CursorEXPLICIT Cursor

Declares a cursor that process more than one row individually.

Declares a cursor that process more than one row individually.

Using Explicit CursorsUsing Explicit CursorsUsing Explicit CursorsUsing Explicit Cursors

Declare the CursorOpen the CursorFetch the CursorClose the Cursor

Declare the CursorOpen the CursorFetch the CursorClose the Cursor

Declaring a Explicit Declaring a Explicit CursorCursor

Declaring a Explicit Declaring a Explicit CursorCursor

While Declaring we have to name it and Associate with a Query.

Declare

CURSOR emp_cursor IS SELECT ename,deptno from emp where sal>2000;

Begin

Opening a Explicit Opening a Explicit CursorCursor

Opening a Explicit Opening a Explicit CursorCursor

Opening the Cursor executes the SELECT statement and Identifies the active set.

OPEN emp_curs;

Opening the Cursor executes the SELECT statement and Identifies the active set.

OPEN emp_curs;

Fetching a Explicit Fetching a Explicit CursorCursor

Fetching a Explicit Fetching a Explicit CursorCursor

Fetch statement retrieves each row in the active set, one at a time.

FETCH emp_cur INTO emp_name;

Fetch statement retrieves each row in the active set, one at a time.

FETCH emp_cur INTO emp_name;

Closing a Explicit Closing a Explicit CursorCursor

Closing a Explicit Closing a Explicit CursorCursor

Close Statement disables the Cursor.

CLOSE emp_curs;

Close Statement disables the Cursor.

CLOSE emp_curs;

C

DEFINE CURSOR

ENAME DEPTNO

SMITHJONESADAMS

20

30

40

CURSOR C is Select Ename,deptno from emp ;

OPEN CURSOR

OPEN C;

ENAME DEPTNO

FETCHING CURSOR

SMITHJONESADAMS

20

30

40

FETCH C INTO ENAM,DEPTN;

CLOSING CURSOR

CLOSE C;

Declareenam varchar(15);depno number(3);CURSOR C Is Select ename,deptno from emp where

job=‘SALESMAN’;BeginOPEN C;LOOPFETCH C into enam,depno ;exit when c%notfound;dbms_output.put_line(enam||depno);END LOOP;Close C;End;

Declareenam varchar(15);depno number(3);CURSOR C Is Select ename,deptno from emp where

job=‘SALESMAN’;BeginOPEN C;LOOPFETCH C into enam,depno ;exit when c%notfound;dbms_output.put_line(enam||depno);END LOOP;Close C;End;

Explicit Cursor AttributesExplicit Cursor Attributes

Every Explicit cursor has four attributes.

Lets you access usefull information about the execution of a multirow query.

Every Explicit cursor has four attributes.

Lets you access usefull information about the execution of a multirow query.

%NOTFOUND%FOUND%ROWCOUNT%ISOPEN

%NOTFOUND%FOUND%ROWCOUNT%ISOPEN

%NOTFOUND%NOTFOUND%NOTFOUND%NOTFOUNDEvaluates to TRUE if the last FETCH

failed because no more rows were

available.

Loop

Fetch emp_cur INTO enam,depno;

EXIT WHEN emp_cur %NOTFOUND;

End loop;

Evaluates to TRUE if the last FETCH

failed because no more rows were

available.

Loop

Fetch emp_cur INTO enam,depno;

EXIT WHEN emp_cur %NOTFOUND;

End loop;

%FOUND%FOUND%FOUND%FOUND Is the Logical Opposite of

%NOTFOUNDLoop Fetch emp_cur INTO enam,detpn; IF emp_cur%FOUND Then Dbms_output.Put_line(‘Record Found’); else exit; End if;End loop;

Is the Logical Opposite of %NOTFOUND

Loop Fetch emp_cur INTO enam,detpn; IF emp_cur%FOUND Then Dbms_output.Put_line(‘Record Found’); else exit; End if;End loop;

%ROWCOUNT%ROWCOUNT%ROWCOUNT%ROWCOUNT

Returns the number of rows FetchedReturns the number of rows Fetched

n:=&number;

open emp_cur;

loop

Fetch emp_cur INTO enam,deptn;

IF emp_cur%ROWCOUNT>n Then

Dbms_output.Put_line('more than '||n||' records');

exit;

End if;

exit when emp_cur%notfound;

End loop; Close emp_cur;

n:=&number;

open emp_cur;

loop

Fetch emp_cur INTO enam,deptn;

IF emp_cur%ROWCOUNT>n Then

Dbms_output.Put_line('more than '||n||' records');

exit;

End if;

exit when emp_cur%notfound;

End loop; Close emp_cur;

%ISOPEN%ISOPEN%ISOPEN%ISOPENChecks Cursor is Opened

Loop

Fetch emp_cur INTO enam,detpn;

IF emp_cur%ISOPEN Then Dbms_output.Put_line(‘Opened’);

End if;

End loop;

Checks Cursor is Opened

Loop

Fetch emp_cur INTO enam,detpn;

IF emp_cur%ISOPEN Then Dbms_output.Put_line(‘Opened’);

End if;

End loop;

Implicit Cursor Implicit Cursor AttributesAttributes

Implicit Cursor Implicit Cursor AttributesAttributes

Use cursor attributes to access the SQL% cursors context area.

%NOTFOUND , %FOUND%ROWCOUNT

%NOTFOUND%NOTFOUND%NOTFOUND%NOTFOUND

Evaluates True if any INSERT,

UPDATE or DELETE affected no Rows.

Update emp set ename=‘RAM’ where

empno=3445;

IF SQL%NOTFOUND then

Evaluates True if any INSERT,

UPDATE or DELETE affected no Rows.

Update emp set ename=‘RAM’ where

empno=3445;

IF SQL%NOTFOUND then

Cursor For LoopsCursor For LoopsCursor For LoopsCursor For Loops It Implicitly OPENS a Cursor,

FETCH each row returned by the query associated with Cursor and CLOSE the Cursor.

Advantages :- Lesser Coding

It Implicitly OPENS a Cursor, FETCH each row returned by the query associated with Cursor and CLOSE the Cursor.

Advantages :- Lesser Coding

declare

cursor lst is select * from emp;

begin

for I in lst loop

dbms_output.put_line(I .ename|| I.job);

end loop;

end;

declare

cursor lst is select * from emp;

begin

for I in lst loop

dbms_output.put_line(I .ename|| I.job);

end loop;

end;

Dynamic CursorsDynamic Cursors

DECLAREDECLARE CURSOR c1 CURSOR c1 (dnum number) IS(dnum number) IS Select * from emp where deptno = dnum;Select * from emp where deptno = dnum;

dep emp.deptno%type; dep emp.deptno%type; BEGIN BEGIN Select deptno into dep from emp Select deptno into dep from emp where ename = where ename = 'SMITH';'SMITH'; FOR emp_rec IN c1(dep) FOR emp_rec IN c1(dep) loop loopDbms_output.put_line(emp_rec.ename)Dbms_output.put_line(emp_rec.ename);; End loop;End loop;END;END;

DECLAREDECLARE CURSOR c1 CURSOR c1 (dnum number) IS(dnum number) IS Select * from emp where deptno = dnum;Select * from emp where deptno = dnum;

dep emp.deptno%type; dep emp.deptno%type; BEGIN BEGIN Select deptno into dep from emp Select deptno into dep from emp where ename = where ename = 'SMITH';'SMITH'; FOR emp_rec IN c1(dep) FOR emp_rec IN c1(dep) loop loopDbms_output.put_line(emp_rec.ename)Dbms_output.put_line(emp_rec.ename);; End loop;End loop;END;END;