- DOI implementation wit unit testing

database/migrations/2021_02_26_153027_create_dataset_identifiers_table.php

@@ -0,0 +1,54 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class CreateDatasetIdentifiersTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::table('dataset_identifiers', function (Blueprint $table) {
+            // primary key
+            $table->increments('id');
+
+            // foreign key to: documents.id
+            $table->integer('dataset_id')->unsigned();
+            ;
+            $table->foreign('dataset_id')->references('id')->on('documents')
+            ->onUpdate('cascade')->onDelete('cascade');
+
+            // value of the identifier
+            $table->string('value', 255);
+            $table->enum(
+                'type',
+                ["doi", "handle", "isbn", "issn",  "url", "urn"]
+            );
+            // DOI registration status
+            $table->enum(
+                'status',
+                ['draft', 'registered', 'findable']
+            )->nullable();
+            // timestamp of DOI registration
+            $table->timestamp('registration_ts');
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::table('dataset_identifiers', function (Blueprint $table) {
+            //
+        });
+    }
+}