trainlog/docs/database.md

Desktop database

1. Status

TRAINLOG_DATABASE_SCHEMA_VERSION=8
DATABASE_SCHEMA_V8=PASS
TRAINLOG_FORMAT_V1=FROZEN

The desktop SQLite database is the canonical long-term Trainlog history.

Its schema evolves independently from all JSON exchange-format versions.

2. Versioning

Schema version uses:

PRAGMA user_version;

Current value:

8

Supported historical databases are migrated explicitly through the implemented migration chain. A database newer than the running binary understands is rejected.

Version 7 assigns session_exercises.entry_id to each stable occurrence. exercise_id remains only the catalogue identity and may occur more than once in a session. The v6 → v7 migration rebuilds the obsolete uniqueness constraint while retaining rows, sets, continuous activities, weights and equipment associations.

Version 8 adds local custom_equipment definitions. The v7 → v8 migration is additive: it retains all historic occurrences and their equipment_id values. Supplied definitions continue to be generated from catalog/equipment-v1.json; custom definitions exist only in the desktop database.

A schema fixture must represent the real historical structure. Rewriting only user_version is not an acceptable migration test.

3. Connection invariants

Every connection enables:

PRAGMA foreign_keys = ON;

A bounded SQLite busy timeout is configured by the core.

4. Tables

exercises

Canonical desktop exercise catalog.

id
exercise_id          UNIQUE stable identity
name
normalized_name      UNIQUE normalized display form
tracking_mode        reps | duration
recording_mode       sets | continuous
data_fields          bounded bit mask

Rules include:

• continuous implies duration tracking;
• unknown supplemental field bits are rejected;
• normalized names remain unique.

sessions

id
session_id           UNIQUE stable identity
started_at
ended_at             nullable
session_type         training | max_test
notes                nullable

session_exercises

Ordered exercise occurrence inside one session.

session_row_id
exercise_row_id
entry_id             UNIQUE stable occurrence identity
recording_mode
data_fields
position
load_mode
rest_seconds
target_sets
target_reps
target_duration_seconds
target_weight_kg
equipment_id         nullable equipment identity
notes

Current desktop history snapshots recording_mode and data_fields in the session row. tracking_mode remains associated with the referenced exercise catalog identity.

An occurrence equipment_id resolves to either a supplied manifest definition or a desktop-local custom_equipment definition. An ID that cannot be resolved is retained as historic data and is explicitly visible to the user; it is never silently converted to NULL.

custom_equipment

Desktop-local custom equipment definitions. They supplement, but do not alter or replace, the supplied catalogue generated from catalog/equipment-v1.json. They synchronize through the separate trainlog-equipment-definitions v1 artifact; session/mobile and association V2 artifacts retain their existing shapes. Definition reconciliation is additive: omission does not delete, an equal same-ID row is idempotent, a divergent same-ID row conflicts, and IDs in the supplied manifest are reserved.

SETS rows support two target shapes in schema v5:

explicit planned target
    target_sets + exactly one target metric

actual-only mobile observation
    target_sets = NULL
    target_reps = NULL
    target_duration_seconds = NULL

This v5 rule is what permits heterogeneous mobile performed sets without inventing a fake uniform target.

CONTINUOUS rows are targetless and require:

load_mode = none
rest_seconds = 0
target_weight_kg = NULL

performed_sets

Ordered actual set records.

session_exercise_row_id
position
reps                 nullable
duration_seconds     nullable
weight_kg            nullable

Exactly one primary actual metric is present:

reps
or
duration_seconds

Actual repetitions may be zero.

Each row is independent; heterogeneous repetition sequences are first-class data.

continuous_activity

One-to-one actual record for a continuous session exercise.

session_exercise_row_id  UNIQUE
duration_seconds
speed_kmh                nullable
distance_km              nullable

Continuous activity never creates a fake performed set.

body_observations

observation_id       UNIQUE
observed_at
session_row_id       optional UNIQUE link
body_weight_kg
neck_cm
shoulders_cm
chest_cm
waist_cm
hips_cm
left_arm_cm
right_arm_cm
left_forearm_cm
right_forearm_cm
left_thigh_cm
right_thigh_cm
left_calf_cm
right_calf_cm
notes

At least one body metric must be present.

5. Identifier generation

Official desktop creator prefixes:

ex_   exercise
se_   session
bo_   body observation
sy_   synchronization run
sxe_  session-exercise occurrence

All use random UUIDv4 values.

Exchange parsers may accept other schema-valid opaque identities where their contract explicitly permits it.

6. Transactions

Multi-row user operations are atomic.

Persisted session correction replaces session child rows transactionally while preserving the parent:

session_id
started_at
ended_at
session_type
session notes
linked body observation

Removing an exercise from a persisted session is therefore a transactional replacement of the remaining child set.

A failed replacement rolls back to the previously persisted session.

Body-observation editing preserves its stable identity, timestamp, and optional session link.

7. Mobile import semantics

tools/import_mobile_export.py validates the complete mobile snapshot before committing database changes.

Properties:

schema-v5-through-v8 aware
transactional
idempotent by stable IDs
profile-aware catalog reconciliation
heterogeneous performed sets preserved
no fake target generated
continuous activity kept separate

For active V2 reconciliation, an identical normalized name never suffices by itself. Different exercise identities may coalesce only when recording and tracking modes match, other represented invariants remain compatible, and their bounded data_fields masks are comparable by inclusion. The existing desktop identity is deterministic canonical ownership. The mask union retains the richer capability, while session_exercises.data_fields and all child values remain unchanged. A missing historic optional value stays NULL. Incomparable masks or modes reject the entire mobile-import transaction.

8. Units

Canonical desktop persistence:

weight/load          kg
body circumference   cm
duration/rest         seconds
speed                 km/h
distance              km

9. Android database

The Android SQLite database is independent.

Current Android-local version: 8. The explicit migration chain adds the durable draft in v4, equipment references in v5, per-set load in v6, occurrence identity/multi-occurrence support in v7, and the widened custom-equipment definition graph in v8.

Table	Ownership
active_session_draft	Single id = 1 row, session type, selected catalog row, raw form text, update time
draft_session_exercises	Ordered draft exercises and profile snapshots
draft_performed_sets	Ordered heterogeneous repetition or duration actuals
draft_continuous_activity	Duration and configured speed/distance without synthetic sets
equipment, equipment_aliases	Supplied and user-created definitions used by selectors and occurrence FKs
exercise_equipment, catalog_exercise_equipment	Persisted manifest relationship metadata retained across migrations and identity reconciliation

Foreign keys remain enabled. Draft deletion cascades only through draft child tables; it cannot delete catalog entries or completed history. The repository commits completed-session insertion and draft removal together, rolling back both on failure. Repeating finalization after success cannot create another completed session. Completed started_at semantics are unchanged by this repair.

Migration tests cover historical v4 and v7 shapes rather than changing only user_version. The prior physical Samsung migration preserved every existing domain row, with successful integrity and foreign-key checks. Current reconciliation validation additionally uses coherent Android and desktop v8 copies whose integrity and foreign keys are checked before and after import. SQLite files are never synchronization artifacts.

The schemas deliberately differ where ownership differs. Desktop sessions own ended_at, notes, planned targets and session-specific load semantics; the Android capture schema does not. Desktop body observations may link to a session and carry notes; Android body observations contain capture metrics only. Android occurrences snapshot tracking_mode as well as recording mode and fields, whereas the current desktop schema resolves tracking mode through the catalog exercise. Desktop stores occurrence equipment_id as stable text so unknown historic IDs remain visible; Android stores a foreign key to its local equipment definition.

Audit limitation: Android persists supplied exercise/equipment relationship tables, but the current session selector searches the complete equipment list instead of filtering or ranking it through those relations. The tables are retained because migration and identity reconciliation already preserve them; making them authoritative UI policy is future catalog work, not a v8 cleanup.

Desktop and Android schema versions are not required to match.

Do not synchronize SQLite database files.

10. Validation

meson compile -C build
meson test -C build --print-errorlogs

Migration-specific regression coverage includes:

schema_v5_migration
schema_v7_migration
exercise_reconciliation

The current normal desktop suite contains 32 tests.

11. Measured-max derivation

Measured maxima require no schema change beyond the current desktop schema v8.

The existing sessions.session_type = max_test classification plus actual performed_sets are sufficient.

Exercise performance points carry the originating session type so the measured-max layer can distinguish explicit tests from ordinary training.

Rules:

training session
    never becomes measured max implicitly

max_test + external
    greatest successful actual load
    tie -> greatest reps/duration

max_test + assistance
    lowest successful assistance
    tie -> greatest reps/duration

max_test + no load
    greatest successful reps/duration

A zero-repetition failed attempt is not a successful measurement.

The current measured result is the newest successful max-test point. The record is the best max-test point using the same load mode.

No extra maximum row is persisted; results are derived from canonical history.

12. Equipment and occurrence migration

Desktop schema v6 added nullable session_exercises.equipment_id. Schema v7 adds the non-null stable entry_id and removes the obsolete UNIQUE(session_row_id, exercise_row_id) constraint. The v6 -> v7 rebuild preserves primary keys, completed sessions, ordered sets, continuous activities, per-set weights and equipment values.

Schema v8 adds local custom_equipment definitions through an additive v7 -> v8 migration. Existing occurrence links remain unchanged. They resolve through the supplied manifest or the local custom table; unknown historic references remain explicit rather than being discarded.

Android schema v6 added nullable weight_kg to completed and durable draft set rows. Schema v7 assigns stable entry_id values to completed and draft occurrences. Actual per-set weights remain independent values, so heterogeneous sets and weights survive edit, finalization, reopen and V2 exchange.

Android schema v8 non-destructively migrates the v7 equipment reference graph so custom definitions may use load_semantics = none. Historic completed occurrences, draft occurrences, and their equipment references remain intact.

13. Body analytics persistence rule

Body analytics require no schema change beyond schema v8.

Canonical persistence continues to contain only measurements actually entered by the user.

These values remain derived at display time and are not persisted:

body-fat estimate
estimated fat mass
estimated lean mass
waist/hip ratio
shoulder/waist ratio
chest/waist ratio
left/right asymmetry percentages

The optional estimation profile is desktop configuration, not database history.