updated db migration

database/migrations/20270101000071-create-quiz-sessions.js

@@ -0,0 +1,31 @@
+'use strict';
+
+// started_at/last_saved_at/createdAt/updatedAt are TIMESTAMP WITHOUT TIME
+// ZONE live (unlike most other tables' TIMESTAMPTZ columns), so raw type
+// strings are used instead of Sequelize.DATE to match exactly.
+module.exports = {
+  async up(queryInterface, Sequelize) {
+    await queryInterface.createTable('quiz_sessions', {
+      session_id:    { type: Sequelize.BIGINT, primaryKey: true, autoIncrement: true },
+      uuid:          { type: Sequelize.UUID, allowNull: false, unique: true, defaultValue: Sequelize.literal('gen_random_uuid()') },
+      user_id:       { type: Sequelize.BIGINT, allowNull: false, references: { model: 'users', key: 'user_id' }, onDelete: 'CASCADE' },
+      quiz_id:       { type: Sequelize.BIGINT, allowNull: false, references: { model: 'unit_quizzes', key: 'quiz_id' }, onDelete: 'CASCADE' },
+      course_id:     { type: Sequelize.BIGINT, allowNull: true },
+      unit_id:       { type: Sequelize.BIGINT, allowNull: true },
+      status:        { type: Sequelize.STRING(20), allowNull: false, defaultValue: 'in_progress' },
+      draft_answers: { type: Sequelize.JSONB, allowNull: true },
+      started_at:    { type: 'TIMESTAMP', allowNull: false, defaultValue: Sequelize.NOW },
+      last_saved_at: { type: 'TIMESTAMP', allowNull: true },
+      createdAt:     { type: 'TIMESTAMP', allowNull: false, defaultValue: Sequelize.NOW },
+      updatedAt:     { type: 'TIMESTAMP', allowNull: false, defaultValue: Sequelize.NOW },
+    });
+
+    await queryInterface.addIndex('quiz_sessions', ['quiz_id'], { name: 'idx_qs_quiz_id' });
+    await queryInterface.addIndex('quiz_sessions', ['status'], { name: 'idx_qs_status' });
+    await queryInterface.addIndex('quiz_sessions', ['user_id'], { name: 'idx_qs_user_id' });
+  },
+
+  async down(queryInterface) {
+    await queryInterface.dropTable('quiz_sessions');
+  },
+};