Spring Boot - Spring JDBC vs Spring Data JDBC

Understanding the difference between Spring JDBC and Spring Data JDBC is important for choosing the right approach to interact with relational databases in Spring Boot applications. Both frameworks serve the same purpose but differ significantly in terms of abstraction, ease of use, and developer productivity. The main difference is:

• Spring JDBC: It requires manual SQL management and boilerplate code.
• Spring Data JDBC: It provides a higher-level abstraction with automatic query generation and reduced boilerplate.

Difference Between Spring JDBC and Spring Data JDBC

The table below demonstrates the difference between Spring JDBC and Spring Data JDBC

Spring JDBC

Spring can perform JDBC operations by having connectivity with any one of jars of RDBMS like MySQL, Oracle, or SQL Server, etc., For example, if we are connecting with MySQL, then we need to connect "mysql-connector-java".  

Let us see how a pom.xml file of a maven project looks like.

pom.xml:

Model Class:

We need a MODEL class to start

DAO Pattern:

Implementation of DAO Interface:

Spring Data JDBC

It belongs to the Spring Data family. Basically, it provides abstractions for the JDBC-based Data Access Layer. It provides easy to use Object Relational Mapping (ORM) framework to work with databases. It can support entity objects and repositories. Because of this, a lot of complexities are reduced. The data access layer is simple. Hence  JPA features like Lazy Loading, caching of entities, etc. are omitted. Because of this JDBC operations on the entities are taken care of well. Let us see what are the dependencies needed for Spring Data JDBC in the Spring Boot maven project.

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jdbc</artifactId>

</dependency>

Let us see what are the dependencies needed for Spring Data JDBC in the Spring maven project.

<dependency>

<groupId>org.springframework.data</groupId>

<artifactId>spring-data-jdbc</artifactId>

<!-- Specify the required version here -->

<version>{version}</version>

</dependency>

POJO Class

For making the entity, we need to use a POJO(Plain old java object). Spring Data JDBC can map our POJO to a database table. The following key points need to be observed

1. Created POJO needs to match with the database table. If not, it uses @Table annotation and this helps to refer to the actual table name.
2. @Id annotation is required to identify the primary key
3. It is a good practice that all the persistence fields in the POJO and database table columns need to match. Otherwise, @Column annotation is helpful to provide column names.

Sample POJO class:

• @Column annotation is not required unless column names differ.
• Lazy loading and relationships are not supported in Spring Data JDBC.

For a POJO class, it is not mandatory to have

1. A parameterized constructor.
2. Access methods.

Repository Interface:

Repository Interface along with Query methods and @Query annotations are supported. Created repositories can be a sub-interface of CrudRepository.

Spring Data JDBC only supports native SQL queries, not JPQL.

The named query can be constructed as,

@Query("SELECT * FROM table_name WHERE column_name = :param")
List<POJOClass> findByColumn(@Param("param") String param);