pl/sql-collection

There are three kinds of collection for pl/sql:

1 nested tables - covered in part 10 of this Oracle PLSQL tutorial

2 varrays - covered in this tutorial

3 PL/SQL associative arrays - covered in part 12 of this PL/SQL tutorial .

 

 1 http://www.smart-soft.co.uk/Oracle/oracle-plsql-tutorial-part-12.htm

   DECLARE

   CURSOR  name_cur  IS
   SELECT  last_name
   FROM  student
   WHERE  rownum  <=   10 ;
  
   -- the nested table is initialized at the time of declaration
   -- Notice that this declaration is very similar to the declaration of an associative array, except that
   -- it has no INDEX BY BINARY_INTEGER clause.
  TYPE last_name_type  IS   TABLE   OF  student.last_name % TYPE;
  last_name_tab last_name_type : =  last_name_type();
  
  v_counter  INTEGER  : =   0 ;
BEGIN
   FOR  name_rec  IN  name_cur LOOP
    v_counter : =  v_counter  +   1 ;
    
     -- In the cursor loop is a statement with one of the collection methods,
     -- EXTEND. This method allows you to increase the size of the collection.
    last_name_tab.EXTEND;
    
    last_name_tab(v_counter) : =  name_rec.last_name;
    DBMS_OUTPUT.PUT_LINE ( ' last_name( ' || v_counter || ' ):  ' ||
    last_name_tab(v_counter));
   END  LOOP;
END ;

 

 

2 http://www.smart-soft.co.uk/Oracle/oracle-plsql-tutorial-part-11.htm

A good example of the use of these would be for storing telephone numbers or addresses for say employees - each person is unlikely to have more than half a dozen telephone numbers or addresses. We can create a table for storing these as follows:-

 

 TYPE phone_no_tab_typ IS VARRAY(6) OF VARCHAR2(20;

phone_nos phone_no_tab_typ;

 

 TYPE varray_type IS VARRAY(10) OF NUMBER;

varray varray_type : =  varray_type( 1 ,  2 ,  3 ,  4 ,  5 ,  6 );

 

 another example as follows: 

DECLARE

   CURSOR  name_cur  IS
   SELECT  last_name
   FROM  student
   WHERE  rownum  <=   10 ;
  
  TYPE last_name_type  IS  VARRAY( 10 )  OF  student.last_name % TYPE;
  last_name_varray last_name_type : =  last_name_type();
  
  v_counter  INTEGER  : =   0 ;
BEGIN
   FOR  name_rec  IN  name_cur LOOP
    v_counter : =  v_counter  +   1 ;
    last_name_varray.EXTEND;
    last_name_varray(v_counter) : =  name_rec.last_name;
    DBMS_OUTPUT.PUT_LINE ( ' last_name( ' || v_counter || ' ):  ' ||
    last_name_varray(v_counter));
   END  LOOP;
END ;

 

 

3 http://www.smart-soft.co.uk/Oracle/oracle-plsql-tutorial-part-10.htm

   DECLARE

   CURSOR  name_cur  IS
   SELECT  last_name
   FROM  student
   WHERE  rownum  <=   10 ;
  
  TYPE last_name_type  IS   TABLE   OF  student.last_name % TYPE
   INDEX BY  BINARY_INTEGER;
  last_name_tab last_name_type;
  
  v_counter  INTEGER  : =   0 ;
BEGIN
   FOR  name_rec  IN  name_cur LOOP
    v_counter : =  v_counter  +   1 ;
    last_name_tab(v_counter) : =  name_rec.last_name;
    DBMS_OUTPUT.PUT_LINE ( ' last_name( ' || v_counter ||
     ' ):  ' || last_name_tab(v_counter));
   END  LOOP;
  
  DBMS_OUTPUT.PUT_LINE ( ' last_name(11):  ' ||
  last_name_tab( 11 ));
END ;

 

 Please pay attention to the index-by table of associative arrays:

 

set  serveroutput  on ;
DECLARE
     type num_tab  is   table   of   varchar2 ( 1000 ) 
      index by  binary_integer;
     
     v_example_tab num_tab;
     v_num  number : = 13 ;
BEGIN
     
    v_example_Tab( -10):='abbb' ;
    dbms_output.put_line(v_example_Tab( - 10 ));
END ;