Table relationship between hierarchy level and merchandise category

Question

1) Want to find Merchadise Category from Merchandise Hierarchy level which is attached with same Merchandise category.
I am having data/TABLE as below.
my input: M_WWG1C_class
i want to fetch data matkl in T023 or matkl in MARA for the same article within same merchandise category.
How i can have link?
2) i am having input CAWN_atwrt(Characteristic Value) and how i can reach matkl in T023 or matkl in MARA  for the same article within same merchandise category.

Answer 1

Oracle does not support REPEATABLE READ transaction isolation level. It only supports SERIALIZABLE, READ COMMITED and READ ONLY isolation levels.
The default is READ COMMITED.
While the READ COMMITED can access all the committed data till the point of execution in transaction, READ SERIALIZABLE can access committed data till the point of start of transaction.
Another difference between two with respect to ROW LEVEL LOCKING is
Both read committed and serializable transactions use row-level locking, and both will wait if they try to change a row updated by an uncommitted concurrent transaction. The second transaction that tries to update a given row waits for the other transaction to commit or roll back and release its lock. If that other transaction rolls back, the waiting transaction, regardless of its isolation mode, can proceed to change the previously locked row as if the other transaction had not existed.
However, if the other blocking transaction commits and releases its locks, a read committed transaction proceeds with its intended update. A serializable transaction, however, fails with the error "Cannot serialize access", because the other transaction has committed a change that was made since the serializable transaction began.
Read following for clearing your concepts on transaction isolation levels and locking mechanisms
http://otn.oracle.com/docs/products/oracle9i/doc_library/release2/server.920/a96524/c21cnsis.htm#2414
Chandar