# `PhoenixMountable.Migrations.SQLite`
[🔗](https://github.com/hattoriai/phoenix_mountable/blob/v0.2.1/lib/phoenix_mountable/migrations/sqlite.ex#L2)

Table rebuilds for SQLite, whose `ALTER TABLE` cannot change a column.

SQLite can add, rename and drop columns, but changing a column's type,
nullability or default means creating a new table, copying the rows and
swapping the tables. Done naively, that drops whatever the host added to
the table. `rebuild_table/3` keeps it:

  * every column of the current table is copied, including columns the
    library does not know about;
  * every index (including unique constraints) and trigger is recreated;
  * foreign keys are kept and checked before committing;
  * a table with `CHECK` constraints or `COLLATE` clauses is refused,
    since they cannot be reproduced reliably, rather than silently lost.

It runs in its own transaction with foreign keys off (dropping a table
with them on would cascade deletes), so the version runs outside the
migration's transaction; `PhoenixMountable.Migration` detects this.

## Changes

    rebuild_table(ctx, :my_lib_items,
      modify: [title: [type: "TEXT", null: false, default: "''"]],
      remove: [:legacy_flag],
      rename: [body: :content]
    )

  * `:modify` — columns to change: `:type` (SQL type), `:null` and
    `:default` (an SQL expression, as a string). Unmentioned attributes
    are kept.
  * `:remove` — columns to drop.
  * `:rename` — columns to rename, `old: :new`.

# `rebuild_table`

```elixir
@spec rebuild_table(
  PhoenixMountable.Migrations.Context.t(),
  atom() | String.t(),
  keyword()
) :: :ok
```

Rebuilds a SQLite table with the given changes. See the module documentation.

---

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