# `PhoenixKitKnowledgeBase.Migrations`
[🔗](https://github.com/BeamLabEU/phoenix_kit_knowledge_base/blob/v0.1.0/lib/phoenix_kit_knowledge_base/migrations.ex#L1)

Versioned migration coordinator for `phoenix_kit_knowledge_base` — the module
returned from `PhoenixKitKnowledgeBase.migration_module/0`.

`mix phoenix_kit.update` discovers this, compares `migrated_version_runtime/1`
(what's installed) with `current_version/0` (what the code needs), and — when
behind — generates a host migration whose `up/0` calls `up/1` here. The host
installs the five knowledge-base tables with no hand-written migration, and it
honors the host's `--prefix` (named-schema installs).

Version is tracked via a `COMMENT ON TABLE` on `phoenix_kit_kb_vaults`
(mirroring core's own `PhoenixKit.Migrations.Postgres` and the pattern
documented in `phoenix_kit_hello_world`'s README) rather than a boolean "does
the table exist", so a future V2 can tell "not installed" apart from
"installed at V1".

## Tables (V1)

| Table | Holds |
|---|---|
| `phoenix_kit_kb_vaults` | One vault — a self-contained note space |
| `phoenix_kit_kb_vault_members` | Per-vault membership (`owner`/`editor`/`viewer`) |
| `phoenix_kit_kb_folders` | The folder tree inside a vault |
| `phoenix_kit_kb_notes` | Markdown notes, tags, and the search vector |
| `phoenix_kit_kb_note_links` | The `[[wiki-link]]` index, including unresolved links |

Versions:

  * `0` — tables absent (not installed)
  * `1` — all five tables present, UUIDv7 primary keys
  * `2` — `phoenix_kit_kb_vaults.path_key`: the vault a drop-in notes panel's
    path names (`notes_panel path={["CRM", …]}`), one shared and one private
    per person per name
  * `3` — paths, link targets and vault directories become `text`. V1 made
    them `varchar(255)`, which a nested folder or a long `[[link]]` overflows:
    the insert raised, a save crashed the page, and one such file made every
    rescan of its vault crash until someone removed it by hand

# `current_version`

```elixir
@spec current_version() :: pos_integer()
```

The version this code expects the schema to be at.

# `down`

```elixir
@spec down(keyword()) :: :ok
```

Roll back. Migration-context only.

# `migrated_version`

```elixir
@spec migrated_version(keyword()) :: non_neg_integer()
```

The version currently installed in the database — 0 if the tables are absent,
and also 0 if they exist but match no version this module knows how to
produce. `up/1` raises with the details for that second case rather than
migrating unrecognised tables blindly.

Migration-context only — reads via `Ecto.Migration.repo/0`.

# `migrated_version_runtime`

```elixir
@spec migrated_version_runtime(keyword()) :: non_neg_integer()
```

Runtime-safe version of `migrated_version/1` — uses PhoenixKit's configured
repo instead of the `Ecto.Migration` `repo()` helper, so it can be called
from Mix tasks and other non-migration contexts (`mix phoenix_kit.update`).

# `up`

```elixir
@spec up(keyword()) :: :ok
```

Run migrations up to (and including) the target version. Migration-context only.

---

*Consult [api-reference.md](api-reference.md) for complete listing*