jobtrackingapp/docs/remaster/DATA_MODEL_REVIEW.md

Data Model Review — Job Tracker

Companion to: SYSTEM_AUDIT_REPORT.md

1. Entities (verified in Models/)

JobApplication, Company, Correspondence, Attachment, JobEvent, TailoredCvDraft(+Json), StructuredCvProfile(+Json), CvExtraction, GmailConnection, GmailReviewDecision, RuleSettings, UserRuleSettings, HumanLanguageCatalog, SystemEmailSettings, ApplicationUser.

2. JobApplication — the god entity [Design flaw]

~40 columns spanning eight distinct concerns on one row:

1. Identity/ownership (Id, OwnerUserId)
2. Core role (JobTitle, CompanyId, Status, DateApplied, Location)
3. Salary — both free-text (Salary) and structured (SalaryMin/Max/Currency/Period)
4. Workflow (NextAction, FollowUpAt, FeedbackRequestedAt, RecruiterMessageDraft)
5. Denormalised attachment flags (HasResume, HasCoverLetter, HasPortfolio, HasOtherAttachment)
6. Soft delete (IsDeleted, DeletedAt)
7. Imported content (Description, TranslatedDescription, DescriptionLanguage, Tags, Deadline, ShortSummary)
8. Tailored CV — both inline (TailoredCvText, TailoredCvUpdatedAt) and related (TailoredCvDraft)

2.1 Denormalisation hazard [Bug risk — High]

HasResume/HasCoverLetter/HasPortfolio/HasOtherAttachment duplicate information already derivable from the Attachments collection. Any code path that adds/removes an attachment without updating the boolean (or vice-versa) produces a silent inconsistency that the attachment-checklist UI will display wrong. These booleans should be computed projections, not stored state. If kept for query performance, they must be maintained in one place (a domain method) — verify no controller mutates them independently.

2.2 Dual tailored-CV source of truth [Design flaw — High]

TailoredCvText (string on JobApplication) vs TailoredCvDraft/TailoredCvDraftJson (related entities). Two writable representations of "the tailored CV for this job" with no documented precedence. This is a classic bug incubator: read one, write the other, and the workspace shows stale content.

2.3 CV "versioning" is not modelled [Design flaw — Medium]

Product step 8 promises "CV version is linked to job." The schema stores a single current tailored text per job, not a version history. There is no CvVersion table with immutable snapshots. The promised capability is only partially real. If versioning matters (it should, for A/B and audit), model it explicitly: CvVersion(id, ownerUserId, sourceProfileId, jobApplicationId?, content, createdAt, label).

3. Relationships

• JobApplication *→1 Company (FK CompanyId) — fine.
• JobApplication 1→* Correspondence / Attachment / JobEvent — fine, but FK columns are unindexed (Correspondence.JobApplicationId, JobEvent.JobApplicationId) → N+1 and slow joins.
• Correspondence.ExternalThreadId powers Gmail continuity (D007/D008) — good, but unindexed.

4. Indexing [Performance — High]

Only OwnerUserId is indexed. Every list/board/reminders/analytics query filters on IsDeleted (unindexed), reminders/background jobs filter on FollowUpAt (unindexed), and detail loads join on the unindexed child FKs. Add: IsDeleted, (IsDeleted, Status), FollowUpAt, Correspondence.JobApplicationId, JobEvent.JobApplicationId. SQLite- and MySQL-safe.

5. Tags/JSON-as-string [Design flaw — Low]

Tags is a JSON-array string; TailoredCvDraftJson/StructuredCvProfileJson are JSON blobs. Workable with EF value converters, but unqueryable. Acceptable given SQLite; revisit if moving fully to MySQL/Postgres (use native JSON columns).

6. Recommended target schema (incremental)

1. Split JobApplication into JobApplication (core+workflow) + JobImportContent (description/translation/ summary/tags) — a 1:1 owned entity — so wide read paths don't drag import blobs.
2. Make attachment booleans computed (drop stored columns after a migration + backfill check).
3. Pick one tailored-CV representation (TailoredCvDraft) and deprecate TailoredCvText.
4. Introduce CvVersion for real versioning.
5. Add the five hot-path indexes (do this first — highest value, lowest risk).

All five are additive/behaviour-preserving migrations guarded by the existing test suite.