Hibernate

Front 1

Write begin and rollback transaction code

Back 1

Session session = sessions.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
concludeAction();
tx.commit();
}catch (Exception e) {
if (tx != null) {
try {
tx.rollback();
}catch(HibernateException he) {
//log & rethrow e;
}
}
throw e;
}finally{
try {
session.close();
}catch(Hibernate he) {
throw he;
}
}

Front 2

For transaction, what is Atomic?

Back 2

Atomic: Several operations are grouped together as a single indivisible unit.

Front 3

For transaction, what is Consistency?

Back 3

Any transaction works with a consistent set of data and leaves the data in a consistent state when the transaction completes.

Front 4

For transaction, what is Isolation?

Back 4

Transactions allow multiple users to work concurrently with the same data without compromising the integrity and correctness of the data; a particular transaction shouldn't be visible to an shouldn't influence other concurrently running transactions.

Front 5

For transaction, what is durability?

Back 5

Once a transaction completes, all changes made during that transaction become persistent state when the transaction completes.

Front 6

What are the isolation issues?

Back 6

Lost update; Dirty read; Unrepeatable read; Second lost updates problem; Phantom read

Front 7

What are the isolation levels?

Back 7

Read uncommitted; Read committed; Repeatable read; Serializable.

Front 8

What is database schema?

Back 8

The objects in a relational database are organized into sets called schemas. A schema is a collection of named objects. The first part of a schema name is the qualifier.