Spring Data JDBC Playground

What this project shows

• A simple blog domain with Authors, Posts, and Comments
• Two relationship styles in Spring Data JDBC:
  • Aggregate children: Post owns a collection of Comment (same aggregate)
  • Aggregate reference: Post references an Author via AggregateReference<Author, Integer> (separate aggregate)
• Basic REST endpoints to read data
• Automatic schema initialization and sample data seeding at startup

Domain model (simplified)

• Author (aggregate root)
  • id, firstName, lastName, email, username
• Post (aggregate root)
  • id, title, content, createdAt, updatedAt
  • author: AggregateReference<Author, Integer> (many posts can reference one author)
  • comments: Set<Comment> (owned children in the Post aggregate)
• Comment (value-like entity within Post aggregate)
  • name, content, publishedAt, updatedAt

Notes on Spring Data JDBC mapping

• Aggregate reference (AggregateReference<Author, Integer>) stores only the foreign key (author id) within post.author column.
• Aggregate children (Comments) are stored in a comment table with a foreign key post pointing to the owning Post.