Add docs for :identity key (#516)

* Add docs for :identity key * Apply suggestions from code review * Update lib/ecto/migration.ex Co-authored-by: Greg Rychlewski <[email protected]> --------- Co-authored-by: José Valim <[email protected]> Co-authored-by: Greg Rychlewski <[email protected]>
elixir-ecto · May 11, 2023 · 859501d · 859501d
1 parent d0b2323
commit 859501d
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/lib/ecto/migration.ex b/lib/ecto/migration.ex
@@ -232,6 +232,13 @@ defmodule Ecto.Migration do
 
  config :app, App.Repo, migration_primary_key: false
 
+ For Postgres version >= 10 `:identity` key may be used.
+ By default, all :identity column will be bigints. You may provide optional
+ parameters for `:start_value` and `:increment` to customize the created
+ sequence. Config example:
+
+ config :app, App.Repo, migration_primary_key: [type: :identity]
+
  * `:migration_foreign_key` - By default, Ecto uses the `primary_key` type
  for foreign keys when `references/2` is used, but you can configure it via:
 
@@ -668,6 +675,10 @@ defmodule Ecto.Migration do
  add :price, :decimal
  end
 
+ create table("users", primary_key: false) do
+ add :id, :identity, primary_key: true, start_value: 100, increment: 20
+ end
+
  ## Options
 
  * `:primary_key` - when `false`, a primary key field is not generated on table
@@ -1035,6 +1046,10 @@ defmodule Ecto.Migration do
  * `:comment` - adds a comment to the added column.
  * `:after` - positions field after the specified one. Only supported on MySQL,
  it is ignored by other databases.
+ * `:start_value` - option for `:identity` key, represents initial value in sequence
+ generation. Default is defined by the database.
+ * `:increment` - option for `:identity` key, represents increment value for
+ sequence generation. Default is defined by the database.
 
  """
  def add(column, type, opts \\ []) when is_atom(column) and is_list(opts) do