aerich/README.md

# Aerich

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## Introduction

Aerich is a database migrations tool for Tortoise-ORM, which is like alembic for SQLAlchemy, or like Django ORM with
it\'s own migration solution.

## Install

Just install from pypi:

```shell
> pip install aerich
```

## Quick Start

```shell
> aerich -h

Usage: aerich [OPTIONS] COMMAND [ARGS]...

Options:
  -c, --config TEXT  Config file.  [default: aerich.ini]
  --app TEXT         Tortoise-ORM app name.  [default: models]
  -n, --name TEXT    Name of section in .ini file to use for aerich config.
                     [default: aerich]
  -h, --help         Show this message and exit.

Commands:
  downgrade  Downgrade to specified version.
  heads      Show current available heads in migrate location.
  history    List all migrate items.
  init       Init config file and generate root migrate location.
  init-db    Generate schema and generate app migrate location.
  inspectdb  Introspects the database tables to standard output as...
  migrate    Generate migrate changes file.
  upgrade    Upgrade to latest version.
```

## Usage

You need add `aerich.models` to your `Tortoise-ORM` config first. Example:

```python
TORTOISE_ORM = {
    "connections": {"default": "mysql://root:123456@127.0.0.1:3306/test"},
    "apps": {
        "models": {
            "models": ["tests.models", "aerich.models"],
            "default_connection": "default",
        },
    },
}
```

### Initialization

```shell
> aerich init -h

Usage: aerich init [OPTIONS]

  Init config file and generate root migrate location.

Options:
  -t, --tortoise-orm TEXT  Tortoise-ORM config module dict variable, like settings.TORTOISE_ORM.
                           [required]
  --location TEXT          Migrate store location.  [default: ./migrations]
  -h, --help               Show this message and exit.
```

Initialize the config file and migrations location:

```shell
> aerich init -t tests.backends.mysql.TORTOISE_ORM

Success create migrate location ./migrations
Success generate config file aerich.ini
```

### Init db

```shell
> aerich init-db

Success create app migrate location ./migrations/models
Success generate schema for app "models"
```

If your Tortoise-ORM app is not the default `models`, you must specify the correct app via `--app`,
e.g. `aerich --app other_models init-db`.

### Update models and make migrate

```shell
> aerich migrate --name drop_column

Success migrate 1_202029051520102929_drop_column.sql
```

Format of migrate filename is
`{version_num}_{datetime}_{name|update}.sql`.

If `aerich` guesses you are renaming a column, it will ask `Rename {old_column} to {new_column} [True]`. You can choose
`True` to rename column without column drop, or choose `False` to drop the column then create. Note that the latter may
lose data.

### Upgrade to latest version

```shell
> aerich upgrade

Success upgrade 1_202029051520102929_drop_column.sql
```

Now your db is migrated to latest.

### Downgrade to specified version

```shell
> aerich init -h

Usage: aerich downgrade [OPTIONS]

  Downgrade to specified version.

Options:
  -v, --version INTEGER  Specified version, default to last.  [default: -1]
  -d, --delete           Delete version files at the same time.  [default:
                         False]

  --yes                  Confirm the action without prompting.
  -h, --help             Show this message and exit.
```

```shell
> aerich downgrade

Success downgrade 1_202029051520102929_drop_column.sql
```

Now your db is rolled back to the specified version.

### Show history

```shell
> aerich history

1_202029051520102929_drop_column.sql
```

### Show heads to be migrated

```shell
> aerich heads

1_202029051520102929_drop_column.sql
```

### Inspect db tables to TortoiseORM model

Currently `inspectdb` only supports MySQL.

```shell
Usage: aerich inspectdb [OPTIONS]

  Introspects the database tables to standard output as TortoiseORM model.

Options:
  -t, --table TEXT  Which tables to inspect.
  -h, --help        Show this message and exit.
```

Inspect all tables and print to console:

```shell
aerich --app models inspectdb
```

Inspect a specified table in the default app and redirect to `models.py`:

```shell
aerich inspectdb -t user > models.py
```

Note that this command is limited and cannot infer some fields, such as `IntEnumField`, `ForeignKeyField`, and others.

### Multiple databases

```python
tortoise_orm = {
    "connections": {
        "default": expand_db_url(db_url, True),
        "second": expand_db_url(db_url_second, True),
    },
    "apps": {
        "models": {"models": ["tests.models", "aerich.models"], "default_connection": "default"},
        "models_second": {"models": ["tests.models_second"], "default_connection": "second", },
    },
}
```

You only need to specify `aerich.models` in one app, and must specify `--app` when running `aerich migrate` and so on.

## License

This project is licensed under the
[Apache-2.0](https://github.com/long2ice/aerich/blob/master/LICENSE) License.