title: TypeORM: Cannot read property 'id' of undefined
body: <p>I tried to using mirgation in TypeORM like this:</p>
  
  <p><strong>TableExample.entity.ts</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>@Entity({ name: 'table_example' })
  export class TableExampleEntity {
  
      constructor(properties : TableExampleInterface) {
          this.id = properties.id;
      }
  
      @PrimaryColumn({
          name: 'id',
          type: 'uuid',
          generated: 'uuid',
          default: 'uuid_generate_v4()',
      })
      id? : string;
  
  }
  </code></pre>
  
  <p><strong>TableExample.interface.ts</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>export interface TableExampleInterface{
      id? : string;
  }
  </code></pre>
  
  <p>and <strong>migration file</strong></p>
  
  <pre class="lang-js prettyprint-override"><code>import {MigrationInterface, QueryRunner, Table} from 'typeorm';
  
  export class createSongEntities1591077091789 implements MigrationInterface {
  
      public async up(queryRunner: QueryRunner): Promise&lt;void&gt; {
          await queryRunner.createTable(new Table({
              name: 'table_example',
              columns: [
                  {
                      name: 'id',
                      type: 'uuid',
                      generationStrategy: 'uuid',
                      default: 'uuid_generate_v4()',
                      isPrimary: true,
                  },
              ],
          }));
      }
  
      public async down(queryRunner: QueryRunner): Promise&lt;void&gt; {
          await queryRunner.dropTable('table_example');
      }
  
  }
  </code></pre>
  
  <p>When run mirgation, node server thrown this error
  Stack trace</p>
  
  <pre><code>Error during migration run:
  TypeError: Cannot read property 'id' of undefined
      at new TableExampleEntity (...\src\entities\TableExample.entity.ts:17:34)
      at EntityMetadata.create (...\src\metadata\EntityMetadata.ts:524:19)
      at EntityMetadataValidator.validate (...\src\metadata-builder\EntityMetadataValidator.ts:112:47)  
      at ...\src\metadata-builder\EntityMetadataValidator.ts:45:56
      at Array.forEach (&lt;anonymous&gt;)
      at EntityMetadataValidator.validateMany (...\src\metadata-builder\EntityMetadataValidator.ts:45:25)
      ...
  </code></pre>
  
  <p>What wrong at here? Please help me!</p>