CODEWITHSUNDEEP
sqllaravelmigration
jc1992
jc1992

Reputation: 644

How to delete only the table relationed

I know how to create the migrations with laravel 5.1 and I have the following code

 public function up()
    {
        Schema::create('articulos', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
            $table->string('content');
            $table->integer('categoria_id')->unsigned();
            $table->integer('creador_id')->unsigned();
            $table->string('slug', 32);
            $table->timestamps();
        });
        Schema::table('articulos', function($table) {
            $table->foreign('categoria_id')->references('id')->on('categorias');
            $table->foreign('creador_id')->references('id')->on('users');
        });
    }

When I try to delete a category with articles , I have an error with foreign key , it's anny possibility to drop this category ?

Upvotes: 1

Views: 52

Answers (1)

Luceos
Luceos

Reputation: 6720

When creating a foreign key constraint, you can also decide what should happen with the constraints. For instance, if you want to delete all articles when a category is deleted (as I guess is your question):

    Schema::table('articulos', function($table) {
        $table->foreign('categoria_id')->references('id')->on('categorias')->onDelete('cascade');
        $table->foreign('creador_id')->references('id')->on('users');
    });

Also see documentation. The cascade identifies to the database that on deletion of a categorias entry, the table should cascade the action into the articulos table.

To further clarify the options in this foreign constraint, you can use:

  • onDelete('set null') to make the column value null once the foreign key is deleted
  • onDelete('restrict') (default behavior) denies deletion of foreign key if still entries exist
  • onDelete('cascade') to automatically delete entries once the foreign key is deleted

More information for MySQL. Please note that foreign key constraint are not necessary for Laravel to support relations. Sometimes you might not need a foreign key.

Also note aside from the onDelete you can also use onUpdate.

Upvotes: 2

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