Oracle creates a memory area, known as context area, for processing an SQL statement, which contains all information needed for processing the statement, for example, number of rows processed, etc. A cursor is a pointer to this context area. PL/SQL controls the context area through a cursor. A cursor holds the rows (one or more) returned by a SQL statement. The set of rows the cursor holds is referred to as the active set. There are two types of cursors: • Implicit Cursors • Explicit Cursors

1. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in

2. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
Assigning SQL Query Results to PL/SQL Variables
You cannot write SQL select statements directly in your PL/SQL block. For example:
BEGIN
SELECT emp_name, emp_salary FROM employee WHERE emp_id=10;
END;
When you run this code this will throw an error.
So to get the result of SQL select statements you have to use INTO clause.
Note: INTO clause is applicable only for single row SELECT statements
So to get assign SQL query results to PL/SQL variables we can use like:
DECLARE
vName varchar2(50);
vSalary number;
BEGIN
SELECT emp_name, emp_salary INTO vName,vSalary
FROM employee WHERE emp_id=10;
dbms_output.put_line(‘Name: ‘||vName||’ and Salary: ‘||vSalary);
END;
This will assign the name of employee to variable vName and salary of employee to variable vSalary
whose employee id is 10. The output will be:
Name: Gurpreet Singh and Salary: 100000

3. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
Now this INTO clause is applicable only for single rows, So if you need to access the multiple rows then?
Then you can use the CURSORS
CURSORS
Oracle creates a memory area, known as context area, for processing an SQL statement, which contains
all information needed for processing the statement, for example, number of rows processed, etc. A
cursor is a pointer to this context area. PL/SQL controls the context area through a cursor. A cursor holds
the rows (one or more) returned by a SQL statement. The set of rows the cursor holds is referred to as
the active set. There are two types of cursors:
 Implicit Cursors
 Explicit Cursors
Implicit Cursors
Implicit cursors are automatically created by Oracle whenever an SQL statement is executed, when there
is no explicit cursor for the statement. Programmers cannot control the implicit cursors and the
information in it.
When you write DML statements (INSERT, UPDATE, DELETE) then implicit cursor gets associated with it.
For example, when we write an INSERT statement then cursor holds the data to be inserted and when we
write DELETE or UPDATE statement then cursor holds the data that will be affected by those statements.
There are various attributes of implicit cursors:
Attribute Description
SQL%FOUND It tells whether any row has been affected with the statement. If one or
more is affected then it returns TRUE otherwise FALSE. For example, for an
update statement, if any row has been affected then it will return TRUE.
SQL%NOTFOUND It is opposite of SQL%FOUND. It returns TRUE if no row has been affected
SQL%ROWCOUNT It tells how many rows have been affected
For example:

4. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
BEGIN
UPDATE employee SET emp_salary=1000 WHERE dept_id=20;
IF SQL%FOUND THEN
dbms_output.put_line(‘Salary of ‘||SQL%ROWCOUNT||’ employees is updated’);
ELSE
dbms_output.put_line(‘Salary not updated of any employee’);
END IF;
END;
Output:
Salary of 4 employees is updated
Explicit Cursors
Explicit cursors are defined by programmer. Explicit cursors are used for those select statements which
return more than one rows.
Working with Explicit Cursors:
 Declare the cursor for initializing in the memory
 Opening the cursor for allocating memory
 Fetching the cursor for retrieving the data
 Closing the cursor to release the allocated memory
For example:
DECLARE OPEN FETCH CLOSE

5. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
DECALRE
CURSOR c1 IS
SELECT emp_id, emp_name FROM employee WHERE dept_id=10;
vId number;
vName varchar2(50);
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO vId, vName;
EXIT WHEN c1%NOTFOUND;
dbms_output.put_line(‘ID: ‘||vId||’ Name: ‘||vName);
END LOOP;
CLOSE c1;
END;
It will display the ID and Name of those employees whose dept_id is 10
We can skip the OPEN, FETCH and CLOSE by using the for loop
DECALRE
CURSOR c1 IS
SELECT emp_id, emp_name FROM employee WHERE dept_id=10;
BEGIN
OPEN c1;
FOR c11 IN c1 LOOP
dbms_output.put_line(‘ID: ‘||c11.emp_id||’ Name: ‘||c11.emp_name);
END LOOP;
END;

6. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
When we use for loop we can access the columns using the loop variable like we have used:
c11.emp_id and c11.emp_name
PASSING VALUES TO CURSORS
We can also pass the values to cursors. For example: in above example we can pass the dept_id rather
than just hard coding it to dept _id=10
DECALRE
CURSOR c1( id number) IS
SELECT emp_id, emp_name FROM employee WHERE dept_id=10;
BEGIN
OPEN c1;
FOR c11 IN c1(10) LOOP --Passing dept_id=10
dbms_output.put_line(‘ID: ‘||c11.emp_id||’ Name: ‘||c11.emp_name);
END LOOP;
END;
DECALRE
CURSOR c1( id number) IS
SELECT emp_id, emp_name FROM employee WHERE dept_id=10;
BEGIN
OPEN c1;
FOR c11 IN c1(20) LOOP --Passing dept_id=20
dbms_output.put_line(‘ID: ‘||c11.emp_id||’ Name: ‘||c11.emp_name);
END LOOP;
END;

7. P L / S Q L T u t o r i a l - B y E r G u r p r e e t S i n g h
Visit: http://gsbprogramming.blogspot.in
Similarly, we can pass other values.
Program to print the sum of salaries of the employees whose salary is greater than 1000
DECALRE
CURSOR c1 IS
SELECT emp_salary FROM employee ORDER BY salary DESC;
vSum number :=0;
BEGIN
OPEN c1;
FOR c11 IN c1 LOOP
IF c11.salary<=1000 THEN
EXIT;
vSum:= vSum+c11.emp_salary;
END LOOP;
dbms_output.put_line(‘Total Sum: ‘||vSum);
END;