# Bylaw.Postgres

Postgres database validation adapter and checks for Bylaw.

This package owns `Bylaw.Db.Adapters.Postgres` and
`Bylaw.Db.Adapters.Postgres.Checks.*`. It also includes Ecto helper modules used
by the changeset constraint checks.

## Installation

Add `bylaw_postgres` to applications that want Postgres database-shape
validation:

```elixir
def deps do
  [
    {:bylaw_postgres, "~> 0.1.0-alpha.1", only: [:dev, :test]}
  ]
end
```

`bylaw_postgres` depends on `bylaw_db`, `ecto_sql`, and `postgrex`; consuming
applications should already have an Ecto SQL repo and Postgres driver available.

## Usage

Most projects run database-shape checks from ExUnit after the test database has
been created and migrated:

```elixir
defmodule MyApp.BylawDbTest do
  use ExUnit.Case, async: false

  alias Bylaw.Db.Adapters.Postgres

  @checks [
    Bylaw.Db.Adapters.Postgres.Checks.MissingForeignKeyIndexes,
    Bylaw.Db.Adapters.Postgres.Checks.MissingForeignKeyConstraints,
    Bylaw.Db.Adapters.Postgres.Checks.ForeignKeyNullability,
    Bylaw.Db.Adapters.Postgres.Checks.DuplicateIndexes
  ]

  test "database structure satisfies Bylaw checks" do
    assert :ok = Postgres.validate(MyApp.Repo, @checks)
  end
end
```

`Postgres.validate/2` validates one repo per call. Pass `:dynamic_repo` to
`validate/3` when a specific dynamic repo should be inspected.

```elixir
test "tenant database structure satisfies Bylaw checks" do
  assert :ok = Postgres.validate(MyApp.Repo, @checks, dynamic_repo: :tenant_one)
end
```

For multiple repos, make separate calls:

```elixir
test "database structure satisfies Bylaw checks" do
  assert :ok = Postgres.validate(MyApp.Repo, @checks)
  assert :ok = Postgres.validate(MyApp.AnalyticsRepo, @checks)
end
```

See each check module's documentation for its examples, notes, and options.