Thursday, 14 June 2012

PLSQL LEARNING CLASS7



COLLECTIONS

Collections are also composite types, in that they allow you to treat several variables as a unit. A collection combines variables of the same type.

TYPES
  • Varrays
  • Nested tables
  • Index - by tables

VARRAYS

A varray is datatype very similar to an array. A varray has a fixed limit on its size, specified as part of the declaration. Elements are inserted into varray starting at index 1, up to maximum lenth declared in the varray type. The maximum size of the varray is 2 giga bytes.

Syntax:
Type <type_name> is varray | varying array (<limit>) of <element_type>;
Ex1:
DECLARE
type t is varray(10) of varchar(2);
va t := t('a','b','c','d');
flag boolean;
BEGIN
dbms_output.put_line('Limit = ' || va.limit);
dbms_output.put_line('Count = ' || va.count);
dbms_output.put_line('First Index = ' || va.first);
dbms_output.put_line('Last Index = ' || va.last);
dbms_output.put_line('Next Index = ' || va.next(2));
dbms_output.put_line('Previous Index = ' || va.prior(3));
dbms_output.put_line('VARRAY ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || '] = ' || va(i));
end loop;
flag := va.exists(3);
if flag = true then
dbms_output.put_line('Index 3 exists with an element ' || va(3));
else
dbms_output.put_line('Index 3 does not exists');
end if;
va.extend;
dbms_output.put_line('After extend of one index, Count = ' || va.count);
flag := va.exists(5);
if flag = true then
dbms_output.put_line('Index 5 exists with an element ' || va(5));
else
dbms_output.put_line('Index 5 does not exists');
end if;
flag := va.exists(6);
if flag = true then
dbms_output.put_line('Index 6 exists with an element ' || va(6));
else
dbms_output.put_line('Index 6 does not exists');
end if;
va.extend(2);
dbms_output.put_line('After extend of two indexes, Count = ' || va.count);
dbms_output.put_line('VARRAY ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || '] = ' || va(i));
end loop;
va(5) := 'e';
va(6) := 'f';
va(7) := 'g';
dbms_output.put_line('AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS,
VARRAY ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || '] = ' || va(i));
end loop;
va.extend(3,2);
dbms_output.put_line('After extend of three indexes, Count = ' || va.count);
dbms_output.put_line('VARRAY ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || '] = ' || va(i));
end loop;
va.trim;
dbms_output.put_line('After trim of one index, Count = ' || va.count);
va.trim(3);
dbms_output.put_line('After trim of three indexs, Count = ' || va.count);
dbms_output.put_line('AFTER TRIM, VARRAY ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || '] = ' || va(i));
end loop;
va.delete;
dbms_output.put_line('After delete of entire varray, Count = ' || va.count);
END;

Output:
Limit = 10
Count = 4
First Index = 1
Last Index = 4
Next Index = 3
Previous Index = 2
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
Index 3 exists with an element c
After extend of one index, Count = 5
Index 5 exists with an element
Index 6 does not exists
After extend of two indexes, Count = 7
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] =
va[6] =
va[7] =
AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS, VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
va[7] = g
After extend of three indexes, Count = 10
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
va[7] = g
va[8] = b
va[9] = b
va[10] = b
After trim of one index, Count = 9
After trim of three indexs, Count = 6
AFTER TRIM, VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
After delete of entire varray, Count = 0
Ex2:
DECLARE
type t is varray(4) of student%rowtype;
va t := t(null,null,null,null);
BEGIN
for i in 1..va.count loop
select * into va(i) from student where sno = i;
dbms_output.put_line('Sno = ' || va(i).sno || ' Sname = ' || va(i).sname);
end loop;
END;

Output:
Sno = 1 Sname = saketh
Sno = 2 Sname = srinu
Sno = 3 Sname = divya
Sno = 4 Sname = manogni

Ex3:
DECLARE
type t is varray(4) of student.smarks%type;
va t := t(null,null,null,null);
BEGIN
for i in 1..va.count loop
select smarks into va(i) from student where sno = i;
dbms_output.put_line('Smarks = ' || va(i));
end loop;
END;

Output:
Smarks = 100
Smarks = 200
Smarks = 300
Smarks = 400

Ex4:
DECLARE
type r is record(c1 student.sname%type,c2 student.smarks%type);
type t is varray(4) of r;
va t := t(null,null,null,null);
BEGIN
for i in 1..va.count loop
select sname,smarks into va(i) from student where sno = i;
dbms_output.put_line('Sname = ' || va(i).c1 || ' Smarks = ' || va(i).c2);
end loop;
END;

Output:
Sname = saketh Smarks = 100
Sname = srinu Smarks = 200
Sname = divya Smarks = 300
Sname = manogni Smarks = 400

Ex5:
DECLARE
type t is varray(1) of addr;
va t := t(null);
cursor c is select * from employ;
i number := 1;
BEGIN
for v in c loop
select address into va(i) from employ where ename = v.ename;
dbms_output.put_line('Hno = ' || va(i).hno || ' City = ' || va(i).city);
end loop;
END;

Output:
Hno = 11 City = hyd
Hno = 22 City = bang
Hno = 33 City = kochi




Ex6:
DECLARE
type t is varray(5) of varchar(2);
va1 t;
va2 t := t();
BEGIN
if va1 is null then
dbms_output.put_line('va1 is null');
else
dbms_output.put_line('va1 is not null');
end if;
if va2 is null then
dbms_output.put_line('va2 is null');
else
dbms_output.put_line('va2 is not null');
end if;
END;

Output:
va1 is null
va2 is not null


NESTED TABLES

A nested table is thought of a database table which has no limit on its size. Elements are inserted into nested table starting at index 1. The maximum size of the varray is 2 giga bytes.

Syntax:
Type <type_name> is table of <table_type>;
Ex1:
DECLARE
type t is table of varchar(2);
nt t := t('a','b','c','d');
flag boolean;
BEGIN
if nt.limit is null then
dbms_output.put_line('No limit to Nested Tables');
else
dbms_output.put_line('Limit = ' || nt.limit);
end if;
dbms_output.put_line('Count = ' || nt.count);
dbms_output.put_line('First Index = ' || nt.first);
dbms_output.put_line('Last Index = ' || nt.last);
dbms_output.put_line('Next Index = ' || nt.next(2));
dbms_output.put_line('Previous Index = ' || nt.prior(3));
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
flag := nt.exists(3);
if flag = true then
dbms_output.put_line('Index 3 exists with an element ' || nt(3));
else
dbms_output.put_line('Index 3 does not exists');
end if;
nt.extend;
dbms_output.put_line('After extend of one index, Count = ' || nt.count);
flag := nt.exists(5);
if flag = true then
dbms_output.put_line('Index 5 exists with an element ' || nt(5));
else
dbms_output.put_line('Index 5 does not exists');
end if;
flag := nt.exists(6);
if flag = true then
dbms_output.put_line('Index 6 exists with an element ' || nt(6));
else
dbms_output.put_line('Index 6 does not exists');
end if;
nt.extend(2);
dbms_output.put_line('After extend of two indexes, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt(5) := 'e';
nt(6) := 'f';
nt(7) := 'g';
dbms_output.put_line('AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS, NESTED TABLE
ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt.extend(5,2);
dbms_output.put_line('After extend of five indexes, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt.trim;
dbms_output.put_line('After trim of one index, Count = ' || nt.count);
nt.trim(3);
dbms_output.put_line('After trim of three indexs, Count = ' || nt.count);
dbms_output.put_line('AFTER TRIM, NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 2..nt.count+1 loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt.delete(4);
dbms_output.put_line('After delete of fourth index, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 2..3 loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
for i in 5..nt.count+2 loop
dbms_output.put_line('nt[' || i || '] = ' || nt(i));
end loop;
nt.delete;
dbms_output.put_line('After delete of entire nested table, Count = ' || nt.count);
END;

Output:
No limit to Nested Tables
Count = 4
First Index = 1
Last Index = 4
Next Index = 3
Previous Index = 2
NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
Index 3 exists with an element c
After extend of one index, Count = 5
Index 5 exists with an element
Index 6 does not exists
After extend of two indexes, Count = 7
NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] =
nt[6] =
nt[7] =
AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS, NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
After extend of five indexes, Count = 12
NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
nt[9] = b
nt[10] = b
nt[11] = b
nt[12] = b
After trim of one index, Count = 11
After trim of three indexs, Count = 8
AFTER TRIM, NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
After delete of first index, Count = 7
NESTED TABLE ELEMENTS
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
After delete of fourth index, Count = 6
NESTED TABLE ELEMENTS
nt[2] = b
nt[3] = c
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
After delete of entire nested table, Count = 0

Ex2:
DECLARE
type t is table of student%rowtype;
nt t := t(null,null,null,null);
BEGIN
for i in 1..nt.count loop
select * into nt(i) from student where sno = i;
dbms_output.put_line('Sno = ' || nt(i).sno || ' Sname = ' || nt(i).sname);
end loop;
END;

Output:
Sno = 1 Sname = saketh
Sno = 2 Sname = srinu
Sno = 3 Sname = divya
Sno = 4 Sname = manogni

Ex3:
DECLARE
type t is table of student.smarks%type;
nt t := t(null,null,null,null);
BEGIN
for i in 1..nt.count loop
select smarks into nt(i) from student where sno = i;
dbms_output.put_line('Smarks = ' || nt(i));
end loop;
END;

Output:
Smarks = 100
Smarks = 200
Smarks = 300
Smarks = 400

Ex4:
DECLARE
type r is record(c1 student.sname%type,c2 student.smarks%type);
type t is table of r;
nt t := t(null,null,null,null);
BEGIN
for i in 1..nt.count loop
select sname,smarks into nt(i) from student where sno = i;
dbms_output.put_line('Sname = ' || nt(i).c1 || ' Smarks = ' || nt(i).c2);
end loop;
END;
Output:
Sname = saketh Smarks = 100
Sname = srinu Smarks = 200
Sname = divya Smarks = 300
Sname = manogni Smarks = 400

Ex5:
DECLARE
type t is table of addr;
nt t := t(null);
cursor c is select * from employ;
i number := 1;
BEGIN
for v in c loop
select address into nt(i) from employ where ename = v.ename;
dbms_output.put_line('Hno = ' || nt(i).hno || ' City = ' || nt(i).city);
end loop;
END;

Output:
Hno = 11 City = hyd
Hno = 22 City = bang
Hno = 33 City = kochi

Ex6:
DECLARE
type t is varray(5) of varchar(2);
nt1 t;
nt2 t := t();
BEGIN
if nt1 is null then
dbms_output.put_line('nt1 is null');
else
dbms_output.put_line('nt1 is not null');
end if;
if nt2 is null then
dbms_output.put_line('nt2 is null');
else
dbms_output.put_line('nt2 is not null');
end if;
END;

Output:
nt1 is null
nt2 is not null



INDEX-BY TABLES

An index-by table has no limit on its size. Elements are inserted into index-by table whose index may start non-sequentially including negative integers.

Syntax:
Type <type_name> is table of <table_type> index by binary_integer;
Ex:

DECLARE
type t is table of varchar(2) index by binary_integer;
ibt t;
flag boolean;
BEGIN
ibt(1) := 'a';
ibt(-20) := 'b';
ibt(30) := 'c';
ibt(100) := 'd';
if ibt.limit is null then
dbms_output.put_line('No limit to Index by Tables');
else
dbms_output.put_line('Limit = ' || ibt.limit);
end if;
dbms_output.put_line('Count = ' || ibt.count);
dbms_output.put_line('First Index = ' || ibt.first);
dbms_output.put_line('Last Index = ' || ibt.last);
dbms_output.put_line('Next Index = ' || ibt.next(2));
dbms_output.put_line('Previous Index = ' || ibt.prior(3));
dbms_output.put_line('INDEX BY TABLE ELEMENTS');
dbms_output.put_line('ibt[-20] = ' || ibt(-20));
dbms_output.put_line('ibt[1] = ' || ibt(1));
dbms_output.put_line('ibt[30] = ' || ibt(30));
dbms_output.put_line('ibt[100] = ' || ibt(100));
flag := ibt.exists(30);
if flag = true then
dbms_output.put_line('Index 30 exists with an element ' || ibt(30));
else
dbms_output.put_line('Index 30 does not exists');
end if;
flag := ibt.exists(50);
if flag = true then
dbms_output.put_line('Index 50 exists with an element ' || ibt(30));
else
dbms_output.put_line('Index 50 does not exists');
end if;
ibt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || ibt.count);
ibt.delete(30);
dbms_output.put_line('After delete of index thirty, Count = ' || ibt.count);
dbms_output.put_line('INDEX BY TABLE ELEMENTS');
dbms_output.put_line('ibt[-20] = ' || ibt(-20));
dbms_output.put_line('ibt[100] = ' || ibt(100));
ibt.delete;
dbms_output.put_line('After delete of entire index-by table, Count = ' || ibt.count);
END;

Output:
No limit to Index by Tables
Count = 4
First Index = -20
Last Index = 100
Next Index = 30
Previous Index = 1
INDEX BY TABLE ELEMENTS
ibt[-20] = b
ibt[1] = a
ibt[30] = c
ibt[100] = d
Index 30 exists with an element c
Index 50 does not exists
After delete of first index, Count = 3
After delete of index thirty, Count = 2
INDEX BY TABLE ELEMENTS
ibt[-20] = b
ibt[100] = d
After delete of entire index-by table, Count = 0


DIFFERENCES AMONG COLLECTIONS

  • Varrays has limit, nested tables and index-by tables has no limit.
  • Varrays and nested tables must be initialized before assignment of elements, in index-by tables we can directly assign elements.
  • Varrays and nested tables stored in database, but index-by tables can not.
  • Nested tables and index-by tables are PL/SQL tables, but varrays can not.
  • Keys must be positive in case of nested tables and varrays, in case of index-by tables keys can be positive or negative.
  • Referencing nonexistent elements raises SUBSCRIPT_BEYOND_COUNT in both nested tables and varrays, but in case of index-by tables NO_DATA_FOUND raises.
  • Keys are sequential in both nested tables and varrays, non-sequential in index-by tables.
  • Individual indexes can be deleted in both nested tables and index-by tables, but in varrays can not.
  • Individual indexes can be trimmed in both nested tables and varrays, but in index-by tables can not.
  • Individual indexes can be extended in both nested tables and varrays, but in index-by tables can not.


MULTILEVEL COLLECTIONS

Collections of more than one dimension which is a collection of collections, known as multilevel collections.

Syntax:
Type <type_name1> is table of <table_type> index by binary_integer;
Type <type_name2> is varray(<limit>) | table | of <type_name1> | index by
binary_integer;
Ex1:
DECLARE
type t1 is table of varchar(2) index by binary_integer;
type t2 is varray(5) of t1;
va t2 := t2();
c number := 97;
flag boolean;
BEGIN
va.extend(4);
dbms_output.put_line('Count = ' || va.count);
dbms_output.put_line('Limit = ' || va.limit);
for i in 1..va.count loop
for j in 1..va.count loop
va(i)(j) := chr(c);
c := c + 1;
end loop;
end loop;
dbms_output.put_line('VARRAY ELEMENTS');
for i in 1..va.count loop
for j in 1..va.count loop
dbms_output.put_line('va[' || i || '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
dbms_output.put_line('First index = ' || va.first);
dbms_output.put_line('Last index = ' || va.last);
dbms_output.put_line('Next index = ' || va.next(2));
dbms_output.put_line('Previous index = ' || va.prior(3));
flag := va.exists(2);
if flag = true then
dbms_output.put_line('Index 2 exists');
else
dbms_output.put_line('Index 2 exists');
end if;
va.extend;
va(1)(5) := 'q';
va(2)(5) := 'r';
va(3)(5) := 's';
va(4)(5) := 't';
va(5)(1) := 'u';
va(5)(2) := 'v';
va(5)(3) := 'w';
va(5)(4) := 'x';
va(5)(5) := 'y';
dbms_output.put_line('After extend of one index, Count = ' || va.count);
dbms_output.put_line('VARRAY ELEMENTS');
for i in 1..va.count loop
for j in 1..va.count loop
dbms_output.put_line('va[' || i || '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
va.trim;
dbms_output.put_line('After trim of one index, Count = ' || va.count);
va.trim(2);
dbms_output.put_line('After trim of two indexes, Count = ' || va.count);
dbms_output.put_line('VARRAY ELEMENTS');
for i in 1..va.count loop
for j in 1..va.count loop
dbms_output.put_line('va[' || i || '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
va.delete;
dbms_output.put_line('After delete of entire varray, Count = ' || va.count);
END;

Output:
Count = 4
Limit = 5
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[1][3] = c
va[1][4] = d
va[2][1] = e
va[2][2] = f
va[2][3] = g
va[2][4] = h
va[3][1] = i
va[3][2] = j
va[3][3] = k
va[3][4] = l
va[4][1] = m
va[4][2] = n
va[4][3] = o
va[4][4] = p
First index = 1
Last index = 4
Next index = 3
Previous index = 2
Index 2 exists
After extend of one index, Count = 5
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[1][3] = c
va[1][4] = d
va[1][5] = q
va[2][1] = e
va[2][2] = f
va[2][3] = g
va[2][4] = h
va[2][5] = r
va[3][1] = i
va[3][2] = j
va[3][3] = k
va[3][4] = l
va[3][5] = s
va[4][1] = m
va[4][2] = n
va[4][3] = o
va[4][4] = p
va[4][5] = t
va[5][1] = u
va[5][2] = v
va[5][3] = w
va[5][4] = x
va[5][5] = y
After trim of one index, Count = 4
After trim of two indexes, Count = 2
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[2][1] = e
va[2][2] = f
After delete of entire varray, Count = 0

Ex2:
DECLARE
type t1 is table of varchar(2) index by binary_integer;
type t2 is table of t1;
nt t2 := t2();
c number := 65;
v number := 1;
flag boolean;
BEGIN
nt.extend(4);
dbms_output.put_line('Count = ' || nt.count);
if nt.limit is null then
dbms_output.put_line('No limit to Nested Tables');
else
dbms_output.put_line('Limit = ' || nt.limit);
end if;
for i in 1..nt.count loop
for j in 1..nt.count loop
nt(i)(j) := chr(c);
c := c + 1;
if c = 91 then
c := 97;
end if;
end loop;
end loop;
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
for j in 1..nt.count loop
dbms_output.put_line('nt[' || i || '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
dbms_output.put_line('First index = ' || nt.first);
dbms_output.put_line('Last index = ' || nt.last);
dbms_output.put_line('Next index = ' || nt.next(2));
dbms_output.put_line('Previous index = ' || nt.prior(3));
flag := nt.exists(2);
if flag = true then
dbms_output.put_line('Index 2 exists');
else
dbms_output.put_line('Index 2 exists');
end if;
nt.extend(2);
nt(1)(5) := 'Q';
nt(1)(6) := 'R';
nt(2)(5) := 'S';
nt(2)(6) := 'T';
nt(3)(5) := 'U';
nt(3)(6) := 'V';
nt(4)(5) := 'W';
nt(4)(6) := 'X';
nt(5)(1) := 'Y';
nt(5)(2) := 'Z';
nt(5)(3) := 'a';
nt(5)(4) := 'b';
nt(5)(5) := 'c';
nt(5)(6) := 'd';
nt(6)(1) := 'e';
nt(6)(2) := 'f';
nt(6)(3) := 'g';
nt(6)(4) := 'h';
nt(6)(5) := 'i';
nt(6)(6) := 'j';
dbms_output.put_line('After extend of one index, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
for j in 1..nt.count loop
dbms_output.put_line('nt[' || i || '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
nt.trim;
dbms_output.put_line('After trim of one indexe, Count = ' || nt.count);
nt.trim(2);
dbms_output.put_line('After trim of two indexes, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
for j in 1..nt.count loop
dbms_output.put_line('nt[' || i || '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
nt.delete(2);
dbms_output.put_line('After delete of second index, Count = ' || nt.count);
dbms_output.put_line('NESTED TABLE ELEMENTS');
loop
exit when v = 4;
for j in 1..nt.count+1 loop
dbms_output.put_line('nt[' || v || '][' || j || '] = ' || nt(v)(j));
end loop;
v := v + 1;
if v= 2 then
v := 3;
end if;
end loop;
nt.delete;
dbms_output.put_line('After delete of entire nested table, Count = ' || nt.count);
END;

Output:
Count = 4
No limit to Nested Tables
NESTED TABLE ELEMENTS
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[1][4] = D
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[2][4] = H
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
nt[3][4] = L
nt[4][1] = M
nt[4][2] = N
nt[4][3] = O
nt[4][4] = P
First index = 1
Last index = 4
Next index = 3
Previous index = 2
Index 2 exists
After extend of one index, Count = 6
NESTED TABLE ELEMENTS
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[1][4] = D
nt[1][5] = Q
nt[1][6] = R
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[2][4] = H
nt[2][5] = S
nt[2][6] = T
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
nt[3][4] = L
nt[3][5] = U
nt[3][6] = V
nt[4][1] = M
nt[4][2] = N
nt[4][3] = O
nt[4][4] = P
nt[4][5] = W
nt[4][6] = X
nt[5][1] = Y
nt[5][2] = Z
nt[5][3] = a
nt[5][4] = b
nt[5][5] = c
nt[5][6] = d
nt[6][1] = e
nt[6][2] = f
nt[6][3] = g
nt[6][4] = h
nt[6][5] = i
nt[6][6] = j
After trim of one indexe, Count = 5
After trim of two indexes, Count = 3
NESTED TABLE ELEMENTS
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
After delete of second index, Count = 2
NESTED TABLE ELEMENTS
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
After delete of entire nested table, Count = 0

Ex3:
DECLARE
type t1 is table of varchar(2) index by binary_integer;
type t2 is table of t1 index by binary_integer;
ibt t2;
flag boolean;
BEGIN
dbms_output.put_line('Count = ' || ibt.count);
if ibt.limit is null then
dbms_output.put_line('No limit to Index-by Tables');
else
dbms_output.put_line('Limit = ' || ibt.limit);
end if;
ibt(1)(1) := 'a';
ibt(4)(5) := 'b';
ibt(5)(1) := 'c';
ibt(6)(2) := 'd';
ibt(8)(3) := 'e';
ibt(3)(4) := 'f';
dbms_output.put_line('INDEX-BY TABLE ELEMENTS');
dbms_output.put_line('ibt([1][1] = ' || ibt(1)(1));
dbms_output.put_line('ibt([4][5] = ' || ibt(4)(5));
dbms_output.put_line('ibt([5][1] = ' || ibt(5)(1));
dbms_output.put_line('ibt([6][2] = ' || ibt(6)(2));
dbms_output.put_line('ibt([8][3] = ' || ibt(8)(3));
dbms_output.put_line('ibt([3][4] = ' || ibt(3)(4));
dbms_output.put_line('First Index = ' || ibt.first);
dbms_output.put_line('Last Index = ' || ibt.last);
dbms_output.put_line('Next Index = ' || ibt.next(3));
dbms_output.put_line('Prior Index = ' || ibt.prior(8));
ibt(1)(2) := 'g';
ibt(1)(3) := 'h';
ibt(1)(4) := 'i';
ibt(1)(5) := 'k';
ibt(1)(6) := 'l';
ibt(1)(7) := 'm';
ibt(1)(8) := 'n';
dbms_output.put_line('Count = ' || ibt.count);
dbms_output.put_line('INDEX-BY TABLE ELEMENTS');
for i in 1..8 loop
dbms_output.put_line('ibt[1][' || i || '] = ' || ibt(1)(i));
end loop;
dbms_output.put_line('ibt([4][5] = ' || ibt(4)(5));
dbms_output.put_line('ibt([5][1] = ' || ibt(5)(1));
dbms_output.put_line('ibt([6][2] = ' || ibt(6)(2));
dbms_output.put_line('ibt([8][3] = ' || ibt(8)(3));
dbms_output.put_line('ibt([3][4] = ' || ibt(3)(4));
flag := ibt.exists(3);
if flag = true then
dbms_output.put_line('Index 3 exists');
else
dbms_output.put_line('Index 3 exists');
end if;
ibt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || ibt.count);
ibt.delete(4);
dbms_output.put_line('After delete of fourth index, Count = ' || ibt.count);
dbms_output.put_line('INDEX-BY TABLE ELEMENTS');
dbms_output.put_line('ibt([5][1] = ' || ibt(5)(1));
dbms_output.put_line('ibt([6][2] = ' || ibt(6)(2));
dbms_output.put_line('ibt([8][3] = ' || ibt(8)(3));
dbms_output.put_line('ibt([3][4] = ' || ibt(3)(4));
ibt.delete;
dbms_output.put_line('After delete of entire index-by table, Count = ' || ibt.count);
END;

Output:
Count = 0
No limit to Index-by Tables
INDEX-BY TABLE ELEMENTS
ibt([1][1] = a
ibt([4][5] = b
ibt([5][1] = c
ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
First Index = 1
Last Index = 8
Next Index = 4
Prior Index = 6
Count = 6
INDEX-BY TABLE ELEMENTS
ibt[1][1] = a
ibt[1][2] = g
ibt[1][3] = h
ibt[1][4] = i
ibt[1][5] = k
ibt[1][6] = l
ibt[1][7] = m
ibt[1][8] = n
ibt([4][5] = b
ibt([5][1] = c
ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
Index 3 exists
After delete of first index, Count = 5
After delete of fourth index, Count = 4
INDEX-BY TABLE ELEMENTS
ibt([5][1] = c
ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
After delete of entire index-by table, Count = 0

Ex3:
DECLARE
type t1 is table of varchar(2) index by binary_integer;
type t2 is table of t1 index by binary_integer;
type t3 is table of t2;
nt t3 := t3();
c number := 65;
BEGIN
nt.extend(2);
dbms_output.put_line('Count = ' || nt.count);
for i in 1..nt.count loop
for j in 1..nt.count loop
for k in 1..nt.count loop
nt(i)(j)(k) := chr(c);
c := c + 1;
end loop;
end loop;
end loop;
dbms_output.put_line('NESTED TABLE ELEMENTS');
for i in 1..nt.count loop
for j in 1..nt.count loop
for k in 1..nt.count loop
dbms_output.put_line('nt[' || i || '][' || j || '][' || k || '] = ' ||
nt(i)(j)(k));
end loop;
end loop;
end loop;
END;

Output:
Count = 2
NESTED TABLE ELEMENTS
nt[1][1][1] = A
nt[1][1][2] = B
nt[1][2][1] = C
nt[1][2][2] = D
nt[2][1][1] = E
nt[2][1][2] = F
nt[2][2][1] = G
nt[2][2][2] = H

OBJECTS USED IN THE EXAMPLES


SQL> select * from student;

SNO SNAME SMARKS
---------- -------------- ----------
1 saketh 100
2 srinu 200
3 divya 300
4 manogni 400

SQL> create or replace type addr as object(hno number(2),city varchar(10));/

SQL> select * from employ;

ENAME JOB ADDRESS(HNO, CITY)
---------- ---------- -----------------------------
Ranjit clerk ADDR(11, 'hyd')
Satish manager ADDR(22, 'bang')
Srinu engineer ADDR(33, 'kochi')




















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