TataKelola dan KamSiber Kecerdasan Buatan v022.pdf
Entity beans in java
1. ENTITY BEAN IN JAVA
Hiren Jamod
Department Of ComputerScience
Saurastra University-Rajkot
2. ENTITY BEANS
Enterprise Beans which represent persistent
data stored in a storage medium, such as a
relational database.
Persists across multiple sessions and can be
accessed by multiple clients.
Each instance of the entity bean represent a row
in the table
EJB container creates instances of an entity bean
and is responsible for loading data in an instance
and storing the information (data) back into the
database.
3. ENTITY BEANS
The persistent mechanisms that enable you to
perform these database manipulations, such as
serialization, Object/Relationship (O/R) mapping
to a relational database and support for JDBC
are built-in the entity bean model
4. CHARACTERISTICS
Persistence
Implies that its state exists even after a client stops
accessing an application
The persistent data remain intact even after the
storage shuts down
Shared Access
Multiple clients can share one entity bean by using
separate instances of the entity bean
EJB Container maintains data consistency by
synchronizing entity bean instances with the
database
To maintain data consistency, the entity beans work
within a transaction
5. CHARACTERISTICS
Primary Key
Each Entity bean has unique identifier; is known
as Primary Key that enables the client to locate
the exact entity bean
Relationships
Like the data of a relational database, the entity
beans are also elated to each other
7. LIFE CYCLE OF ENTITY BEANS
Initially, the beans do not exist
When the Application server this stage to the Pooled
stage
When the server is first started, several bean
instances are created and placed in the pool.
A bean instance in the pooled state is not ties to
particular data
At this stage, the beans are referred as passivated.
The bean remains in this stage till the client does
not make a request for it or the container does not
activate it.
8. LIFE CYCLE OF ENTITY BEANS
The bean’s business methods can be invoked
when the bean is at the ready stage.
It remains at this stage till the client calls its
remove method or the container passiveness it if
the bean has been lying idle for sometimes