防止播种唯一的密钥违规

Question

I have a unique constraint in my database for two columns.

$table->unique(array("table_a_id", "table_b_id"));

Now I use Faker in a seeder class to fill in this pivot table:

$tableAIds = TableA::all()->lists("id")->toArray();
$tableBIds = TableB::all()->lists("id")->toArray();

foreach(range(1, 20) as $index) {
    $tableAId = $faker->randomElement($tableAIds);
    $tableBId = $faker->randomElement($tableBIds);

    DB::table("table_a_table_b_pivot")->insert([
        "table_a_id" => $tableAId,
        "table_b_id" => $tableBId
    ]);
}

However this creates duplicates and the seeding fails due to SQL error.

How do I make sure I don't try to insert duplicates?

Answer 1

Instead of using faker, use the collection's random method:

$tableAIds = TableA::all()->lists('id')->random(20);
$tableBIds = TableB::all()->lists('id')->random(20);

foreach(range(0, 19) as $index) {
    DB::table("table_a_table_b_pivot")->insert([
        "table_a_id" => $tableAIds[$index],
        "table_b_id" => $tableBIds[$index],
    ]);
}

Adjust this according to your needs.

For example, this might be what you really want:

$tableAIds = TableA::all()->lists('id');
$tableBIds = TableB::all()->lists('id');

foreach ($tableAIds->random(5) as $tableAId) {
    foreach ($tableBIds->random(2) as $tableBId) {
        DB::table("table_a_table_b_pivot")->insert([
            "table_a_id" => $tableAId,
            "table_b_id" => $tableBId,
        ]);
    }
}

Whatever it is, play with it yourself. No need for faker here.