feat: Single event JDBC insert/update [DHIS2-21378]

[enricocolasante]

feat: Single event JDBC insert/update DHIS2-21378

Summary

Continues the Hibernate→JDBC tracker import migration (Phase 6) by moving SingleEvent writes off EntityManager and onto raw JDBC, following the same pattern already established for
TrackedEntity, Enrollment and TrackerEvent. SingleEvent mirrors the TrackerEvent shape, writing to the dedicated singleevent table (split out per V2_43_21__split_event_table.sql)
— without enrollmentid (single events aren't tied to an enrollment) and without scheduleddate. This includes cascade-handling for event notes (previously managed by Hibernate via
@OneToMany(cascade=ALL)) and JSON serialization of the eventdatavalues jsonb column. Like TrackerEvent, SingleEvent is not L2-cached, so no cache removal was required.

Changes

EntityWriteBatch — the bulk of the work:

• SingleEvent inserts are now flushed via a multi-row JDBC INSERT into singleevent. Ids are pre-allocated from singleevent_sequence by AbstractTrackerPersister.
• SingleEvent updates are flushed via a single JDBC unnest UPDATE against singleevent, writing only the columns mutated by TrackerObjectsMapper.mapSingleEvent on the update
  branch. Insert-only columns (uid, created, createdbyuserinfo, deleted) and externally-owned columns (lastsynchronized) are deliberately excluded.
• eventdatavalues is serialized as a JSON object keyed by dataElement uid, matching JsonEventDataValueSetBinaryType, so the on-disk shape is byte-identical to the Hibernate-written
  value.
• SingleEvent notes are cascade-inserted in two further multi-row INSERTs (note and the singleevent_notes join table), replacing Hibernate's cascade behaviour. New note ids are
  allocated from note_sequence; sort_order is derived from the 1-based list position. Notes are append-only on update — only notes with id == 0 are treated as new. The note-row insert
  logic is shared with the enrollment / tracker-event paths via the NoteToInsert abstraction.
• Applies the same L1-staleness fix used for the other entity types: after the JDBC UPDATE bypasses Hibernate, the preheat-loaded managed SingleEvent is detached so any subsequent
  JPQL read reloads fresh DB state (the reload also picks up the notes appended later in the flush).
• Removes the now-unused mergeAll helper.

AbstractTrackerPersister:

• assignId now handles SingleEvent (in addition to TrackedEntity, Enrollment and TrackerEvent) for pre-allocated ids.

SingleEventPersister:

• sequenceName() now returns singleevent_sequence (was null), enabling id pre-allocation.

Notes

• Relationship and TEAV writes still delegate to EntityManager; their Phase 6 JDBC replacements follow.
• Sequence clean-up (to do before/with this PR's merge): per the migration plan, the single-events PR carries the sequence rename for the already-migrated entity types — rename the
  legacy sequences trackedentityinstance_sequence (TrackedEntity) and programinstance_sequence (Enrollment) so all migrated entity types use sequence names matching their current entity
  names.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
3 Accepted issues

Measures
2 Security Hotspots
0.0% Coverage on New Code
10.3% Duplication on New Code

See analysis details on SonarQube Cloud