hello,

I have a table defined so:

$table->unsignedInteger('id');
            $table->integer('shipment_id')->nullable();
            $table->integer('customer_id');
            $table->integer('address_id');
            $table->string('appointed')->nullable();
            $table->string('causal')->nullable();
            $table->string('quantity')->nullable();
            $table->string('weight')->nullable();
            $table->string('appearance')->nullable();
            $table->string('carriage')->nullable();
            $table->date('transport_time')->nullable();
            $table->unsignedInteger('year')->default(date('Y'));

            $table->primary(array('id', 'year'));

            $table->timestamps();

now I need to have another table, with foreign key:

$table->unsignedInteger('id');
            $table->unsignedInteger('ddt_id');
            $table->unsignedInteger('year')->default(date('Y'));
            $table->string('code')->nullable();
            $table->text('description');
            $table->string('quantity')->nullable();

            $table->primary(array('id', 'ddt_id', 'year'));
            $table->foreign('ddt_id')->references('id')->on('ddts')->onDelete('cascade');
            $table->foreign('year')->references('year')->on('ddts')->onDelete('cascade');

            $table->timestamps();

but obviously when I migrate I get:

General error: 1215 Cannot add foreign key constraint (SQL: alter table ddtrows add constraint ddtrows_year_foreign foreign key (year) references ddts (year) on delete cascade)

how do I set foreign key in this case?

thanks a lot