My DB is running with out Backup and also DB is in NO Archive log mode.How to find out the below issue.

The following problem occured during DB operation:
ORA-01115: IO error reading block from file 11 (block # 236928)
ORA-27072: File I/O error
Additional information: 4
Additional information: 236928
Additional information: 409600
ORA-01115: IO error...

While developing sopping cart application we have to create a main catagory and the admin want facillity that he can add the unlimited number of subcatagories and the subcatagories again having unlimited number of subcatagories. So how to create catagory table to perform this tree like structure

What is Upper and Lower Checkpoint?

What is the difference between Subquery and Corelated Subquery?Give some examples of each

Explain how the cursor can become stuck between two items, resulting in a navigation trap.

How to load data onto db2 environment other than FTP