Interested to Buy Any Domain ? << Click Here >> for more details...
Wat is isolation level and when do u use them?
- 1 Answers
- 20970 Views
- HP, IBM, I also Faced
- E-Mail Answers
Answer Posted / ram
Specifies the transaction isolation levels that provide the
necessary
consistency and concurrency control between transactions in
the job and
other transactions for optimal performance.
Because Oracle does not
prevent other transactions from modifying the data read by
a query, that
data may be changed by other transactions between two
executions of the
query. Thus, a transaction that executes a given query
twice may
experience both nonrepeatable reads and phantoms. Use one
of the following
transaction isolation levels:
Read Committed. Takes exclusive locks on modified data and
sharable locks
on all other data. Each query executed by a transaction
sees only data
that was committed before the query (not the transaction)
began. Oracle
queries never read dirty, that is, uncommitted data. This
is the default.
Serializable. Takes exclusive locks on modified data and
sharable locks on
all other data. It sees only those changes committed when
the transaction
began plus those made by the transaction itself through
INSERT, UPDATE,
and DELETE statements. Serializable transactions do not
experience
nonrepeatable reads or phantoms.
Read-only. Sees only those changes that were committed when
the
transaction began. This level does not permit INSERT,
UPDATE, and DELETE
statements.
| Is This Answer Correct ? | 2 Yes | 3 No |
Post New Answer View All Answers
Is it possible to implement parallelism in Mainframe Jobs ? If Yes how ? If no why ?
Can we use target hash file as a lookup ?
How do you run datastage job from the command line?
how to read 100 records at a time in source a) hw is it fr metadata Same and b) if metadata is nt same?
Explain the importance of surrogate key in data warehousing?
Differentiate between datastage and informatica?
How will you move hashed file from one location to another location?
Hi,can any one please mention list of dimension and fact tables for Sales and Distribution System for a Pharmacutical company.
What is active and passive stage?
How can we improve the performance in datastage?
Can you define merge?
There are two file are there .1st file contains 5 records and 2nd file contain 10 records in target they want 50 records.how can achieve this
What are the steps needed to create a simple basic datastage job?
what is 'reconsideration error' and how can i respond to this error and how to debug this
How to manage date conversion in Datastage?
