PL/SQL Tables

Like an array, a PL/SQL table is an ordered collection of elements of the same type. Each element has a unique index number that determines its position in the ordered collection. But, unlike an array, a PL/SQL table is unbounded. So, its size can increase dynamically. Also, it does not require consecutive index numbers. So, it can be indexed by any series of integers. 
PL/SQL tables help you move bulk data. They can store columns or rows of Oracle data, and they can be passed as parameters. So, PL/SQL tables make it easy to move collections of data into and out of database tables or between client-side applications and stored subprograms. 

You can use a cursor FOR loop to fetch an entire column or table of Oracle data into a PL/SQL table. In the following example, you fetch a table of data into the PL/SQL table dept_tab:

DECLARE
   TYPE DeptTabTyp IS TABLE OF dept%ROWTYPE
      INDEX BY BINARY_INTEGER;
   dept_tab DeptTabTyp;
   n BINARY_INTEGER := 0;
BEGIN
   FOR dept_rec IN (SELECT * FROM dept) LOOP
      n := n + 1;
      dept_tab(n) := dept_rec;
   END LOOP;
   ...
END;