Ecto migrate brings automatic migrations to ecto. Instead of defining and writting manuall diffing
from actual model and old model. The ecto_migrate do it for you. It save actual represantation of
a model model in database and checks, if actual model have the same format as saved in database.
To test, use EctoIt (is depended on it for tests purposes):
iex -S mix
After, it should be possible:
:application.start(:ecto_it)
alias EctoIt.Repo
import Ecto.Query
defmodule Weather do # is for later at now
use Ecto.Model
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
end
Ecto.Migration.Auto.migrate(Repo, Weather)
%Weather{city: "Berlin", temp_lo: 20, temp_hi: 25} |> Repo.insert
Repo.all(from w in Weather, where: w.city == "Berlin")Lets redefine the same model in a shell and migrate it
defmodule Weather do # is for later at now
use Ecto.Model
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
field :wind, :float, default: 0.0
end
end
Ecto.Migration.Auto.migrate(Repo, Weather)
Repo.all(from w in Weather, where: w.city == "Berlin")Lets use references
defmodule Post do
use Ecto.Model
schema "posts" do
field :title, :string
field :public, :boolean, default: true
field :visits, :integer
has_many :comments, Comment
end
end
defmodule Comment do
use Ecto.Model
schema "comments" do
field :text, :string
belongs_to :post, Post
end
end
Ecto.Migration.Auto.migrate(Repo, Post)
Ecto.Migration.Auto.migrate(Repo, Comment)ecto_migrate also provides additional migrate/3 API. For using with custom source defined models. Example:
defmodule Taggable do
use Ecto.Model
schema "this is not a valid schema name and it will never be used" do
field :tag_id, :integer
end
end
defmodule MyModel do
use Ecto.Model
schema "my_model" do
field :a, :string
has_many :my_model_tags, {"my_model_tags", Taggable}, [foreign_key: :tag_id]
end
endNow we can migrate my_model_tags table with:
Ecto.Migration.Auto.migrate(Repo, MyModel)
Ecto.Migration.Auto.migrate(Repo, Taggable, [for: MyModel])It will generate and migrate my_model_tags table to the database which will be associated with my_model table.
ecto_migrate has support of indexes:
defmodule Weather do # is for later at now
use Ecto.Model
use Ecto.Migration.Auto.Index
index(:city, unique: true)
index(:prcp)
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
endIf you do not want to use DSL for defining indexes, macro index doing no more, as generate function:
defmodule Weather do # is for later at now
use Ecto.Model
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
def __indexes__ do
[{[:city], [unique: true]},
{[:prpc], []}]
end
enddefmodule Weather do # is for later at now
use Ecto.Model
use Ecto.Migration.Auto.Index
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
def __attribute_option__(:city), do: [size: 40]
def __attribute_option__(_), do: []
endIf the same model used by different sources, it is possible to define callback for it
defmodule Weather do # is for later at now
use Ecto.Model
use Ecto.Migration.Auto.Index
schema "weather" do
field :city
field :temp_lo, :integer
field :temp_hi, :integer
field :prcp, :float, default: 0.0
end
def __sources__, do: ["weather", "history_weather"]
endIf you have installed version before 0.3.2, use 0.3.2 or 0.3.3 for upgrading the table, after that it is possible to upgrade higher versions.