Laravel 在迁移中删除外键

Laravel drop foreign Key in Migration

提问by Jon not doe xx

I want to create a Migration which shall drop a table. I created the Migration like this:

我想创建一个将删除表的迁移。我创建了这样的迁移：

Schema::table('devices', function (Blueprint $table) {
    $table->increments('id');
    $table->unsignedInteger('client_id')->nullable();
    $table->foreign('client_id')->references('id')->on('clients')->onDelete('cascade');
});

And now I try to drop it like this:

现在我试着像这样放下它：

    Schema::table('devices', function (Blueprint $table) {
        $table->dropForeign('devices_client_id_foreign');
        $table->drop('devices');
    });

But I get following error:

但我收到以下错误：

In Connection.php line 664:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists (SQL:

alter table devicesdrop foreign key devices_client_id_foreign)

In PDOStatement.php line 144:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists


In PDOStatement.php line 142:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists

In Connection.php line 664:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists (SQL:

改变表devices删除外键devices_client_id_foreign）

In PDOStatement.php line 144:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists


In PDOStatement.php line 142:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'devices_client_id_foreign'; check that column/key exists

采纳答案by Jason Grim

You just need to disable foreign key checks before you drop the table then enable them again after like this:

您只需要在删除表之前禁用外键检查，然后像这样再次启用它们：

DB::statement('SET FOREIGN_KEY_CHECKS=0;');
Schema::dropIfExists('devices');
DB::statement('SET FOREIGN_KEY_CHECKS=1;');

回答by gandarrillas

You can use this answer. https://stackoverflow.com/a/30177480/8513937

你可以使用这个答案。https://stackoverflow.com/a/30177480/8513937

Pass to dropForeignthe column name as array. Internally, Laravel drops the associated foreign key.

将列名作为数组传递给dropForeign。在内部，Laravel 删除关联的外键。

$table->dropForeign(['client_id']);

回答by Jonas Staudenmeir

Just drop the whole table (documentation):

只需删除整个表（文档）：

Schema::drop('devices');

回答by Laurazel8

Try this ways...

试试这些方法...

  public function down()
 {
    Schema::dropIfExists('devices');
 }

//Or this
  public function down(){
    Schema::table('devices', function (Blueprint $table) {
        $table->dropForeign(['client_id']);
        $table->dropColumn('client_id');
        $table->drop('devices');
    });
  }