# `AshScylla.Migrator`
[🔗](https://github.com/ohhi-vn/ash_scylla/blob/main/lib/ash_scylla/migrator.ex#L15)

Thin wrapper for executing CQL schema migrations via Xandra directly.

Replaces the Exandra/Ecto.Migration pattern. Since CQL has no transactional
DDL, each statement is executed independently.

## Usage

Start a temporary connection for migrations:

    AshScylla.Migrator.run("127.0.0.1:9042", [
      "CREATE KEYSPACE IF NOT EXISTS my_app " <>
      "WITH REPLICATION = {'class': 'SimpleStrategy', 'replication_factor': 1}",
      "CREATE TABLE IF NOT EXISTS my_app.users (id UUID PRIMARY KEY, name TEXT)"
    ])

In a Mix task or release task:

    AshScylla.Migrator.run!(nodes, statements,
      keyspace: "my_app",
      connect_timeout: 10_000
    )

## Functions

- `run/3` — Start temp connection, execute statements, stop connection
- `run!/3` — Same as `run/3` but raises on error
- `run_on/2` — Execute against an existing named connection
- `run_on!/2` — Same as `run_on/2` but raises on error

# `run`

```elixir
@spec run(String.t() | [String.t()], [String.t()], keyword()) ::
  {:ok, [term()]} | {:error, {non_neg_integer(), term()}}
```

Executes a list of CQL statements against a ScyllaDB node.

A temporary connection is started, all statements are executed sequentially,
and the connection is stopped.

Returns `{:ok, results}` or `{:error, {failed_index, reason}}`.

# `run!`

```elixir
@spec run!(String.t() | [String.t()], [String.t()], keyword()) ::
  [term()] | no_return()
```

Same as `run/3` but raises on error.

# `run_on`

```elixir
@spec run_on(atom(), [String.t()]) ::
  {:ok, [term()]} | {:error, {non_neg_integer(), term()}}
```

Executes CQL statements against an existing named connection.

# `run_on!`

```elixir
@spec run_on!(atom(), [String.t()]) :: [term()] | no_return()
```

---

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