asmhatre
807f681ed1
Same payment hierarchy mapped three ways plus @MappedSuperclass, run with plain Hibernate on H2. Tests assert and write the generated DDL, the INSERT/SELECT SQL, row/insert/FK/nullability counts and the three failures (NOT NULL on a SINGLE_TABLE subclass column, IDENTITY with TABLE_PER_CLASS, querying a @MappedSuperclass); Bench writes indicative polymorphic-query timings. No docs folder: depth lives in the post.
2.6 KiB
2.6 KiB
inheritance
Companion module for the ankurm.com article on Hibernate 7 inheritance mapping: SINGLE_TABLE vs JOINED vs
TABLE_PER_CLASS. One payment hierarchy (a root with card, bank-transfer and wallet subclasses, plus an order that
points at the root) mapped three ways, run against plain Hibernate (no Spring) and in-memory H2, with every statement
Hibernate generates captured in output/.
Versions
| Component | Version | Notes |
|---|---|---|
| Hibernate ORM | 7.4.13.Final |
latest 7.x GA on Maven Central on 2026-10-24 (8.0.0.Beta3 is also listed; it is not GA) |
| Jakarta Persistence | 3.2.0 |
|
| H2 | 2.4.240 |
in memory, OPTIMIZE_REUSE_RESULTS=0 (see Db.java) |
| JUnit Jupiter / AssertJ | 6.0.3 / 3.27.7 |
|
| Java | 25 (Temurin 25.0.5+8) |
This module has its own pom.xml and does not use the Spring Boot parent of the main hibernate-demo project, so its
Hibernate patch version differs from the one that project pins.
Run
./scripts/run-all.sh # JUnit tests, then the timing run; regenerates everything in output/
./scripts/bench.sh # only the timing run
Layout
| Path | What it is |
|---|---|
src/main/java/com/ankurm/inheritance/single |
Payment hierarchy, SINGLE_TABLE, discriminator column, @Check constraint |
src/main/java/com/ankurm/inheritance/joined |
the same hierarchy, JOINED |
src/main/java/com/ankurm/inheritance/tpc |
the same hierarchy, TABLE_PER_CLASS (sequence ids, abstract root) |
src/main/java/com/ankurm/inheritance/mapped |
@MappedSuperclass AuditedBase with two unrelated entities |
src/test/java/.../Strategies.java |
the three hierarchies side by side |
src/test/java/.../DdlTest.java |
writes output/01-* |
src/test/java/.../SqlTest.java |
writes output/02-* |
src/test/java/.../ContractsTest.java |
writes output/03-contracts.txt; also holds the two deliberately wrong mappings (Sn*, TpcIdentity*) |
src/test/java/.../Bench.java |
writes output/04-polymorphic-timings.txt |
Output
| File | What it shows |
|---|---|
output/01-ddl-single-table.txt, 01-ddl-joined.txt, 01-ddl-table-per-class.txt, 01-ddl-mapped-superclass.txt |
the schema Hibernate generates |
output/02-sql-single-table.txt, 02-sql-joined.txt, 02-sql-table-per-class.txt |
INSERTs and SELECTs for the same four operations |
output/03-contracts.txt |
row counts, INSERT counts, nullability, foreign keys, and the three failures |
output/04-polymorphic-timings.txt |
indicative timings on 150,000 rows (not asserted; drift between runs) |
Everything in 01-03 is produced by tests that assert the numbers they print.