Drops.Relation.Plugins.AutoRestrict (drops_relation v0.1.0)

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Plugin that automatically generates finder functions based on database indices.

This plugin analyzes the relation's schema indices and generates composable finder functions like get_by_email/1, get_by_name/1, etc. These functions are automatically available on any relation module that includes this plugin.

Generated Functions

For each database index, this plugin generates corresponding finder functions:

  • Single column index on email → get_by_email/1
  • Single column index on name → get_by_name/1
  • Composite index on email, role → get_by_email_and_role/2
  • Composite index on user_id, status → get_by_user_id_and_status/2

Examples

Single Column Index Finders

iex> # Find user by email (unique index)
iex> user_query = MyApp.Users.get_by_email("john@example.com")
iex> user = MyApp.Users.one(user_query)
iex> user.name
"John Doe"
iex> user.email
"john@example.com"

iex> # Find users by name (non-unique index)
iex> users_query = MyApp.Users.get_by_name("Jane Smith")
iex> users = MyApp.Users.all(users_query)
iex> length(users)
1
iex> hd(users).name
"Jane Smith"

Composite Index Finders

iex> # Find by composite index (name + age)
iex> user_query = MyApp.Users.get_by_name_and_age("John Doe", 30)
iex> user = MyApp.Users.one(user_query)
iex> user.name
"John Doe"
iex> user.age
30

Composable with Other Operations

iex> # Chain with restrictions
iex> active_user = MyApp.Users.get_by_email("john@example.com")
...>   |> MyApp.Users.restrict(active: true)
...>   |> MyApp.Users.one()
iex> active_user.name
"John Doe"
iex> active_user.active
true

iex> # Chain with ordering
iex> ordered_users = MyApp.Users.get_by_name("John Doe")
...>   |> MyApp.Users.order(:age)
...>   |> MyApp.Users.all()
iex> length(ordered_users)
1
iex> hd(ordered_users).age
30

Blog Posts Example

iex> # Find posts by user (foreign key index)
iex> user_posts = MyApp.Posts.get_by_user_id(1)
...>   |> MyApp.Posts.restrict(published: true)
...>   |> MyApp.Posts.order(desc: :view_count)
...>   |> MyApp.Posts.all()
iex> length(user_posts)
1
iex> hd(user_posts).title
"First Post"
iex> hd(user_posts).published
true

Function Behavior

All generated functions return relation structs that can be:

  • Executed with one/1, all/1, etc.
  • Composed with restrict/2, order/2, preload/2
  • Used with Enum functions for further processing

The functions are named using the pattern get_by_<column> for single columns and get_by_<column1>_and_<column2> for composite indices.