| 284 | | > '''Student action required.''' Open `ERModel_v03.xml` in TerraER and read it |
| 285 | | > end to end before submission — see the note at the end of |
| 286 | | > ERModel. Everything else in this session's diff is already |
| 287 | | > applied to the docs and to `server/`. |
| | 285 | |
| | 286 | === Session 4 — 2026-09-24 (Claude Opus 5.5): v04 after P7 === |
| | 287 | |
| | 288 | '''Prompts (student, verbatim):''' |
| | 289 | > But this order_events is added after Phase 7 right? can we add that too? |
| | 290 | |
| | 291 | > can you make the ERmodel again with TerraER file to update it? and tell that after P7 we added this |
| | 292 | |
| | 293 | > Make it with a white background like earier versions |
| | 294 | |
| | 295 | '''Response (AI, summarised):''' |
| | 296 | |
| | 297 | * Explained that the P7 changes must also appear in P1 and P2, since both must describe the current data structure. |
| | 298 | * Built `ERModel_v04.xml` in TerraER's own file format by taking `ERModel_v03.xml` unchanged and appending the new elements with the same XML structure TerraER uses: |
| | 299 | * the attribute `reserved_balance` on `Users`; |
| | 300 | * the attribute `filled_quantity` on `Orders`; |
| | 301 | * the relationships `FillsBuy` and `FillsSell` (Orders 1 : N !MarketTrades, partial); |
| | 302 | * the entity set `OrderEvents` (key `id`, `event_type`, `quantity`, `price`, `status_after`, `created_at`) with `Logs` (Orders 1 : N !OrderEvents, total on !OrderEvents). |
| | 303 | * Rendered `ERModel_v04.png` with TerraER 3.14's own drawing classes (loading the `.xml` exactly as TerraER does and using its image export), on a white background and trimmed like the earlier versions. |
| | 304 | * Updated [wiki:ERModel] (title v.04, new attribute rows, the `OrderEvents` section, the three relationships, and a v04 history entry stating these were added after P7). |
| | 305 | |
| | 306 | '''What I decided:''' to add the P7 structure to the ER model. The new elements are placed |
| | 307 | automatically, so the layout can be tidied by hand in TerraER. |
| | 308 | |
| | 309 | === Session 5 — 2026-09-29 (Claude Opus 5.5): v05, correction after review === |
| | 310 | |
| | 311 | '''Prompt (student, excerpt):''' I pasted the reviewer's comments that `Holds` and `Contains` |
| | 312 | are implemented differently in the database than in the model, with the suggestion to |
| | 313 | "correct only the Phase 1 model so that it matches Phase 2", and asked: |
| | 314 | |
| | 315 | > Can you take a look at this stuff? and fix them, but don't push anything just make the |
| | 316 | > changes requested and try to explain it to me to see if you understand the problem with |
| | 317 | > the solution |
| | 318 | |
| | 319 | '''Response (AI, summarised):''' |
| | 320 | |
| | 321 | * Explained that an M:N relationship has no identifier of its own, while `holdings` and `watchlist_items` each have an `id` primary key, so the database treats them as entity sets. |
| | 322 | * Changed the model to v05. `Holdings` (`id`, `quantity`, `reserved_quantity`, derived `avg_price`, `created_at`, `updated_at`) and `WatchlistItems` (`id`, `added_at`) became entity sets, with the 1:N relationships `Holds`, `PositionIn`, `Contains` and `Lists`, each total on the new entity's side. The old relationship keys are now stated as uniqueness rules. The key descriptions no longer name foreign-key columns. |
| | 323 | * Generated `ERModel_v05.xml` / `ERModel_v05.png` from scratch with TerraER 3.11's own figure classes and writer (adapted from the v01 generator), on a grid, with no overlapping attributes. It was verified by reading the file back with TerraER's reader (184 figures) and by inspecting the rendered PNG. |
| | 324 | * Updated [wiki:ERModel] (v05 sections and history entry). |
| | 325 | |
| | 326 | '''What I decided:''' to follow the reviewer's advice and change the model rather than the |
| | 327 | database, since every later phase already uses the database as it is. |
