# Slice 2 — multi-tenancy and product editions

xly is a multi-tenant SaaS. The same codebase, the same database schema, the
same metadata tables serve many customers — and within one customer, many
subsidiaries — and across customers, several product *editions* (基础版,
EBC-MDM, EBC-SD, EBC-RD, …). This slice traces how that scoping is enforced.

Multi-tenancy is fundamental: get it wrong and one customer reads another
customer's orders. So this slice is one of the most security-relevant
chapters in the wiki.

## Three scoping axes

xly's tenancy has **three** dimensions, applied at different layers:

| Axis | Carried in | Granularity | Used for |
|---|---|---|---|
| **`sBrandsId`** (加工商ID) | Almost every business row | Per-row | "Which manufacturer/company owns this row?" |
| **`sSubsidiaryId`** (子公司ID) | Almost every business row | Per-row | "Which subsidiary within the company?" |
| **`sVersionFlowId`** (版本流程ID) | `gdsmodule` only | Per-module | "Which product edition is this module part of?" |

The first two are **per-row** scoping. The third is **per-module** filtering
applied at module-list load time. Different mechanisms, different layers.

## Per-row scoping (`sBrandsId` + `sSubsidiaryId`)

### How wide

Of `xlyweberp_saas_ai`'s 1,212 tables/views, **1,008 carry both `sBrandsId`
and `sSubsidiaryId`** as columns. That's nearly every business-data table
and every framework-metadata table — almost the whole schema.

### How they're injected

Every authenticated REST endpoint runs the same call right after the request
arrives:

```java
RequestAddParamUtil.me().addParams(params, userInfo);
```

`RequestAddParamUtil` lives at
`xlyPersist/src/main/java/com/xly/utils/RequestAddParamUtil.java` (44 lines —
short and worth reading in full). It pulls the authenticated user's identity
out of `UserInfo` and writes thirteen keys into the request `params` map,
including:

- `sBrandsId` — the manufacturer/company id
- `sSubsidiaryId` — the subsidiary id
- `sBrId` / `sSuId` — short aliases used in some procs
- `sLoginId`, `sUserId`, `sUserType`, `sLanguage` — the rest of the auth
  context

Every downstream MyBatis query and stored-procedure call that references
`#{sBrandsId}` / `#{sSubsidiaryId}` is then automatically scoped. The
frontend cannot influence these values — they come from the server-side
session via the `@CurrentUser` argument resolver.

### How it shows up in queries

The Slice-1 `getModelBysId` call ended up reading metadata via:

```sql
WHERE sBrandsId = #{sBrandsId} AND sSubsidiaryId = #{sSubsidiaryId}
```

…on every metadata table (`gdsmodule`, `gdsconfigformmaster`,
`gdsconfigformslave`, `gdsformconst`, `gdsjurisdiction`, `sysbillnosettings`).
The same predicate appears in essentially every business-data query in the
codebase. This is the multi-tenancy boundary at runtime.

### Failure mode

A query that *forgets* to filter by `sBrandsId` would return rows from every
tenant. That's the catastrophic data-leak case. Slice 1 already raised this
as a security concern in the save-endpoint context (the frontend supplies
`sTable` directly); the same concern recurs whenever a stored procedure or
MyBatis mapper omits the tenant predicate. The wiki's
[Maintainer Reference on permissions](../reference/maintainer/runtime.md)
should call this out.

## Per-edition filtering (`sVersionFlowId`)

### What "edition" means

xly is sold in several editions: **基础版** (Essentials), **EBC-MDM** (Master
Data Management), **EBC-SD** (Sales/Delivery), **EBC-RD** (R&D), and others.
Each edition exposes a different set of modules. A 基础版 customer doesn't
see Premium modules; a Premium customer sees everything Essentials sees plus
extras.

### Where editions are defined

The `sisversionflow` table (1 row in this dev DB):

| Column | Value | Meaning |
|---|---|---|
| `sId` | `17551378250008601172639655149000` | Edition primary key |
| `sCode` | `8S_001` | Short code referenced by `gdsmodule.sVersionFlowCode` |
| `sFlowName` | `基础版` | Display name |
| `bEbcErpPremium`, `bEbcMes`, `bEbcMesStandard`, `bSass` | flags | Which product variants this edition belongs to |

In the live SaaS, expect more rows here — one per distinct edition. The
`EBC-MDM-002`, `EBC-SD-002`, `EBC-RD-007` flow codes seen in `gdsmodule`
correspond to rows we'd find in a multi-edition production DB.

### How modules are filtered per edition

`sVersionFlowId` is **only** on three tables:

- `gdsmodule` (the live module catalog)
- `gdsmodule_0923bak` (a backup snapshot)
- `gdsmodule_copy1` (another snapshot)

So per-edition filtering applies **only at module-discovery time**, not on
every business-data query. When a user logs in, the framework resolves which
edition their tenant is on, then filters the visible module list to those
matching `gdsmodule.sVersionFlowId`. From there, every loaded module reads
its data with `sBrandsId`/`sSubsidiaryId` scoping as normal.

In `xlyweberp_saas_ai` the picture (`SELECT … COUNT(*) FROM gdsmodule
GROUP BY sVersionFlowId, sVersionFlowCode`):

| Flow code | Modules tagged | What it covers |
|---|---|---|
| `8S_001` (基础版) | 322 | Essentials baseline |
| `EBC-SD-002` | 15 | Sales/Delivery |
| `EBC-RD-007` | 6 | R&D |
| `EBC-MDM-002` | 5 | Master-data management |
| `EBC-SD-001`, `EBC-SD-003`, `EBC_001`, `EBC-COM-001`, *(blank)* | a handful each | Various extensions |

The 322 Essentials-tagged modules are the universally-licensed core. The
others are edition-specific add-ons.

## Why dev looks small

The `xlyweberp_saas_ai` schema this wiki is written from has **one** brand
(`sBrandsId = '1111111111'`), **one** subsidiary (same value), and **one**
populated edition (`8S_001`). The multi-tenancy machinery is wired but
barely exercised. In production, expect dozens of brands × dozens of
subsidiaries × multiple editions, all isolated through the same per-row
filter pattern.

## Concepts this slice introduces

- *Multi-tenant scoping* (new concept page) — `sBrandsId`/`sSubsidiaryId`
  as the per-row tenant boundary; the framework's universal injector
  (`RequestAddParamUtil`).
- *Product editions* (new concept page) — `sVersionFlowId` against
  `sisversionflow` as the per-module visibility filter; the difference
  between scoping (per-row) and gating (per-module).

These will be added to Concepts as part of the next backfill pass.

## Reference entries this slice exercises

**Maintainer track:**

- [The runtime](../reference/maintainer/runtime.md) — `RequestAddParamUtil`
  belongs in the runtime chapter as the universal tenant-context injector.
- New page: *Multi-tenant query patterns* — the conventions every MyBatis
  mapper and every stored procedure must follow to stay tenant-safe.

## Open verification items

1. **Module-discovery filtering by edition.** The mechanism is reasonable
   (filter `gdsmodule` by `sVersionFlowId` against the user's edition), but
   we haven't located the exact code path. Likely candidate:
   `GdsmoduleController` or `GdsmoduleServiceImpl`. Confirm.
2. **Activiti workflow** — `sVersionFlowId` is *not* a workflow id (despite
   the name "flow"). The actual workflow tables (`act_*`, `biz_flow`,
   `gdsmoduleflow`, `sysflowsendtointerface`) are all empty in this dev DB.
   A future Slice 7 will document workflow once a DB with active flows is
   available.
3. **Session-level tenant resolution.** How the JWT/session lookup actually
   maps a logged-in user to `sBrandsId`/`sSubsidiaryId` (and which
   middleware enforces it) is one layer below `RequestAddParamUtil`. Worth
   tracing in the maintainer chapter.