JPA
&
HIBERNATE
@rohanthapa
Java Persistence API (JPA)
The Java Persistence API (JPA) is a specification for
object-relational mapping (ORM) in Java.
It standardizes the way Java objects are mapped to
relational database tables, simplifying data access
and manipulation.
Key Concepts:
1.Entity:
An entity represents a table in a database.
Each entity instance corresponds to a row in the
table.
Key Concepts:
2. EntityManager:
The EntityManager is the primary interface for
interacting with the persistence context.
It provides methods for CRUD operations,
querying, and managing entity instances.
Key Concepts:
3. Persistence Unit:
A persistence unit defines a set of entity classes
that are managed together.
It is configured in the persistence.xml file.
4. JPQL (Java Persistence Query Language):
JPQL is similar to SQL but operates on entity
objects rather than database tables.
It supports queries for entity retrieval and
manipulation.
Advantages of JPA
Standardization: JPA provides a standardized
approach to ORM, ensuring compatibility and
consistency across different JPA
implementations.
Productivity: JPA reduces boilerplate code,
allowing developers to focus on business logic
rather than data access code.
Portability: Applications written using JPA are
portable across different databases and
environments.
Hibernate
Hibernate is an open-source ORM framework that
implements JPA.
It provides advanced features and optimizations for
database interactions.
Key Features
1.Automatic Table Creation:
Hibernate can automatically generate database
tables based on entity mappings.
Key Features
2. Caching:
Hibernate supports first-level and second-level
caching to improve performance.
First-level cache is associated with the session
and is enabled by default.
Second-level cache is associated with the session
factory and is optional.
Key Features
3. Lazy Loading:
Lazy loading delays the loading of related entities
until they are accessed.
4. Batch Processing:
Hibernate can optimize batch operations to
improve performance.
Key Features
5.Custom SQL:
Hibernate allows the use of native SQL queries if
needed.
Advantage of Hibernate
Rich Feature Set: Hibernate offers many
advanced features not covered by JPA, such as
caching, lazy loading, and batch processing.
Maturity and Stability: Hibernate is widely
adopted and has been extensively tested in
various enterprise applications.
Community and Support: Hibernate has an active
user community and extensive documentation.
Integrating JPA and Hibernate with
Spring Boot
Spring Boot simplifies the setup and configuration of
JPA and Hibernate. Here’s how to get started:
Dependencies: Add the necessary dependencies to
your pom.xml (for Maven) or build.gradle (for
Gradle).
Maven:
Integrating JPA and Hibernate with
Spring Boot
Basic Setup:
1. Entity Class: Define your entity class with JPA
annotations.
Integrating JPA and Hibernate with
Spring Boot
2. Repository Interface: Create a repository interface
for data access.
3. Application Properties: Configure the database
connection in application.properties.
Common JPA and HIbernate
Annotations
1.@Entity:
Marks a class as an entity.
2. @Table:
Specifies the table name
3. @Id:
Specifies the primary key.
Common JPA and HIbernate
Annotations
4. @GeneratedValue:
Specifies the generation strategy for the primary
key.
5. @Column:
Specifies the column details.
6. @OneToOne, @OneToMany, @ManyToOne,
@ManyToMany:
Defines relationships between entities
Common JPA and HIbernate
Annotations
7. @JoinColumn:
Specifies the foreign key column
8. @Query:
Defines custom JPQL or native SQL queries
9. @Cacheable:
Enables second-level caching for an entity
Conclusion
JPA and Hibernate are essential tools for modern
Java applications, offering a robust and flexible
framework for data persistence and management.
By integrating JPA and Hibernate with Spring Boot,
developers can leverage the power of these
technologies while enjoying the benefits of Spring
Boot’s simplicity and ease of use.
Whether you are building a simple CRUD application
or a complex enterprise system, understanding and
utilizing JPA and Hibernate will significantly enhance
your development process and application
performance.
Thank You
