Spring JDBC

spring-boot-starter-jdbc

• handles the connection to a database
• lets you execute SQL via JdbcTemplate

Spring Data JDBC

spring-boot-starter-data-jdbc

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• uses entities with additional rules (the class structure needs to follow the aggregate design of DDD)
  • basically, we group entities together which have strong coupling and call them aggregates
  • the top entity of the aggregate is called the aggregate root
  • some other rules:
    • an entity can only be part of 1 aggregate
    • all relations inside an aggregate need to be unidirectional
    • the aggregate root needs to manage to top relation
    • entity classes within aggregates can only have one-to-one and/or one-to-many relationships
• because of the rules, every entity within an aggregate can be found starting with the root
• because of the above premise, do not need a repository for each entity like in spring-data-jpa but only for aggregate roots
• following things supported by Spring Data JPA but not Spring Data JDBC
  • supports query methods in (v2.0)
  • does not support persistence context like Spring Data JPA does
  • a big difference between spring-data-jpa and spring-data-jdbc is that no @Entity and no relation annotations (e.g. @OneToMany) need to be used. Spring Data JDBC knows a class is an aggregate root when it contains a repository for that class. And because the rules of the aggregate entities are connected through object references (i.e. one-to-one are object reference, and one-to-many is a collection of objects) Spring Data JDBC also knows what the aggregates are and can transfer data to the database as aggregates.

Spring Data JPA

spring-boot-starter-data-jpa

• uses entities
• for relational typed databases
• has more abstractions than Spring Data JDBC

Spring Data MongoDB

spring-boot-starter-data-mongodb

• for MongoDB

Spring Data Neo4j

spring-boot-starter-data-neo4j

• for Neo4j

Spring Data Elastic Search

spring-boot-starter-data-elasticsearch

• for Elasticsearch