I have done following process,
1. A schema was called BOOK
2.And under that I have created one table called CUSTOMER.
3. Data has been inserted through 'insert into'
4. Data is showing for the table from Data Preview.
5. Now a Package called "book" has been created
6. Next I have created an Attribute View for the table CUSTOMER
7. Key Attribute and normal attribute has been done too.
Now, when I go to Data Preview, to see the data of Attribute View, No data is coming and same time no error message is appearing too !!!