chore: created base migration and schema for students records and cla…

…sses relationship

- created `students_records_classes` table
- created `StudentsRecords.StudentRecordClassRelationship` schema
- added classes fields to `StudentRecord` schema

lib/lanttern/students_records/student_record.ex

@@ -8,9 +8,11 @@ defmodule Lanttern.StudentsRecords.StudentRecord do
 
   import LantternWeb.Gettext
 
+  alias Lanttern.StudentsRecords.StudentRecordClassRelationship
   alias Lanttern.StudentsRecords.StudentRecordRelationship
   alias Lanttern.StudentsRecords.StudentRecordStatus
   alias Lanttern.StudentsRecords.StudentRecordType
+  alias Lanttern.Schools.Class
   alias Lanttern.Schools.School
   alias Lanttern.Schools.Student
 
@@ -21,6 +23,9 @@ defmodule Lanttern.StudentsRecords.StudentRecord do
           date: Date.t(),
           time: Time.t(),
           students: [Student.t()],
+          students_ids: [pos_integer()],
+          classes: [Class.t()],
+          classes_ids: [pos_integer()],
           school_id: pos_integer(),
           school: School.t(),
           status_id: pos_integer(),
@@ -37,17 +42,21 @@ defmodule Lanttern.StudentsRecords.StudentRecord do
     field :date, :date
     field :time, :time
     field :students_ids, {:array, :id}, virtual: true
+    field :classes_ids, {:array, :id}, virtual: true
 
     belongs_to :school, School
     belongs_to :status, StudentRecordStatus
     belongs_to :type, StudentRecordType
 
     has_many :students_relationships, StudentRecordRelationship, on_replace: :delete
+    has_many :classes_relationships, StudentRecordClassRelationship, on_replace: :delete
 
     many_to_many :students, Student,
       join_through: "students_students_records",
       preload_order: [asc: :name]
 
+    many_to_many :classes, Class, join_through: "students_records_classes"
+
     timestamps()
   end
 
@@ -60,12 +69,14 @@ defmodule Lanttern.StudentsRecords.StudentRecord do
       :date,
       :time,
       :students_ids,
+      :classes_ids,
       :school_id,
       :type_id,
       :status_id
     ])
     |> validate_required([:description, :date, :school_id, :type_id, :status_id])
     |> cast_and_validate_students()
+    |> cast_classes()
   end
 
   def cast_and_validate_students(changeset) do
@@ -96,4 +107,21 @@ defmodule Lanttern.StudentsRecords.StudentRecord do
   end
 
   defp cast_students(changeset, _), do: changeset
+
+  defp cast_classes(changeset) do
+    case get_change(changeset, :classes_ids) do
+      classes_ids when is_list(classes_ids) ->
+        school_id = get_field(changeset, :school_id)
+
+        classes_relationships_params =
+          Enum.map(classes_ids, &%{class_id: &1, school_id: school_id})
+
+        changeset
+        |> put_change(:classes_relationships, classes_relationships_params)
+        |> cast_assoc(:classes_relationships)
+
+      _ ->
+        changeset
+    end
+  end
 end

lib/lanttern/students_records/student_record_class_relationship.ex

@@ -0,0 +1,22 @@
+defmodule Lanttern.StudentsRecords.StudentRecordClassRelationship do
+  @moduledoc """
+  The `StudentRecordClassRelationship` schema (join table)
+  """
+
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @primary_key false
+  schema "students_records_classes" do
+    field :student_record_id, :id, primary_key: true
+    field :class_id, :id, primary_key: true
+    field :school_id, :id
+  end
+
+  @doc false
+  def changeset(student_record_class_relationship, attrs) do
+    student_record_class_relationship
+    |> cast(attrs, [:class_id, :student_record_id, :school_id])
+    |> validate_required([:class_id, :student_record_id, :school_id])
+  end
+end

lib/lanttern/students_records/student_record_relationship.ex

@@ -16,7 +16,7 @@ defmodule Lanttern.StudentsRecords.StudentRecordRelationship do
   @doc false
   def changeset(student_record_relationship, attrs) do
     student_record_relationship
-    |> cast(attrs, [:student_id, :student_record_i, :school_id])
+    |> cast(attrs, [:student_id, :student_record_id, :school_id])
     |> validate_required([:student_id, :student_record_id, :school_id])
   end
 end

priv/repo/migrations/20241212195844_create_students_records_classes.exs

@@ -0,0 +1,28 @@
+defmodule Lanttern.Repo.Migrations.CreateStudentsRecordsClasses do
+  use Ecto.Migration
+
+  def change do
+    # creating unique constraints to allow composite foreign keys.
+    # this guarantees, in the database level, that record and class
+    # belong to the same school
+
+    # removing existing "classes_school_id_index" to prevent unnecessary index
+    drop index(:classes, [:school_id])
+    create unique_index(:classes, [:school_id, :id])
+
+    create table(:students_records_classes, primary_key: false) do
+      # in the future we will handle how to cascade class and school deletion to ss records
+      add :class_id, references(:classes, with: [school_id: :school_id], on_delete: :nothing),
+        null: false
+
+      add :student_record_id,
+          references(:students_records, with: [school_id: :school_id], on_delete: :delete_all),
+          null: false
+
+      add :school_id, references(:schools, on_delete: :nothing), null: false
+    end
+
+    create index(:students_records_classes, [:class_id])
+    create unique_index(:students_records_classes, [:student_record_id, :class_id])
+  end
+end