Oracle Database Discussions

Hi,

I am using below bind values in a sql query.

declare
B1 number;
B2 varchar2(10);
B3 varchar2(10);
B4 number;
B5 date;
B6 date;
B7 varchar2(30);
B8 number;
B9 number;
B10 varchar2(9);
B11 number;
Begin
:B1 := 24152;
:B2 := 'CR_CORP';
:B3 := 'COST';
:B4 := 24152;
B5 := TO_DATE('01/29/12 23:20:34','MM/DD/YY HH24:MI:SS');
B6 := TO_DATE('02/27/12 21:10:58','MM/DD/YY HH24:MI:SS');
:B7 := 'BEGIN';
:B8 := 945142827;
:B9 := 483695;
:B10 := 'CR_CORP';
:B11 := 7;
End;
/
and even tried as below:
declare
variable B1 number;
variable B2 varchar2(30);
variable B3 varchar2(30);
variable B4 number;
B5 date;
B6 date;
variable B7 varchar2(30);
variable B8 number;
variable B9 number;
variable B10 varchar2(30);
variable B11 number;
Begin
:B1 := 24152;
:B2 := 'CR_CORP';
:B3 := 'COST';
:B4 := 24152;
B5 := TO_DATE('01/29/12 23:20:34','MM/DD/YY HH24:MI:SS');
B6 := TO_DATE('02/27/12 21:10:58','MM/DD/YY HH24:MI:SS');
:B7 := 'BEGIN';
:B8 := 945142827;
:B9 := 483695;
:B10 := 'CR_CORP';
:B11 := 7;
End;
/

Resulting in SP2-0552: Bind variable "B7" not declared.
Kindly help!