数据库、ORM 以及关系等常用操作

$users = DB::table('users')->get();

// 按条件查询单个
$user = DB::table('users')->where('name', 'John')->first();
// 查询不到抛异常
$user = DB::table('users')->where('name', 'John')->firstOrFail();
// 查询单条记录并返回 email 字段值
$email = DB::table('users')->where('name', 'John')->value('email');
// 按 ID 查询
$user = DB::table('users')->find(3);

// 获取表中所有 title 字段值
$titles = DB::table('users')->pluck('title');

// 获取表中所有 title 字段值，并以 name 字段值为键
$titles = DB::table('users')->pluck('title', 'name');

// 存在
DB::table('orders')->where('finalized', 1)->exists();

// 不存在
DB::table('orders')->where('finalized', 1)->doesntExist();

DB::table('users')->insert([
    'email' => 'kayla@example.com',
    'votes' => 0
]);

DB::table('users')->insert([
    ['email' => 'picard@example.com', 'votes' => 0],
    ['email' => 'janeway@example.com', 'votes' => 0],
]);

$affected = DB::table('users')
    ->where('id', 1)
    ->update(['votes' => 1]);

DB::table('users')
    ->updateOrInsert(
        ['email' => 'john@example.com', 'name' => 'John'],
        ['votes' => '2']
    );

// votes +1
DB::table('users')->increment('votes');
// votes +5
DB::table('users')->increment('votes', 5);

// votes -1 
DB::table('users')->decrement('votes');
// votes -5
DB::table('users')->decrement('votes', 5);

// votes +1, 并更新其他字段值
DB::table('users')->increment('votes', 1, ['name' => 'John']);

// 删除所有记录
$deleted = DB::table('users')->delete();

// 删除符合条件的记录
$deleted = DB::table('users')->where('votes', '>', 100)->delete();

// 按条件查询
$flight = Flight::where('active', 1)->first();

// 按 ID 查询
$flight = Flight::find(1);

// 按 name 查询，或不存在时创建
$flight = Flight::firstOrCreate([
    'name' => 'London to Paris'
]);
// 按 name 查询，或使用合并后的数组新建
$flight = Flight::firstOrCreate(
    ['name' => 'London to Paris'],
    ['delayed' => 1, 'arrival_time' => '11:30']
);

// 和上面区别在于只会创建实例，并不会持久化到数据库
$flight = Flight::firstOrNew([
    'name' => 'London to Paris'
]);

$flight = Flight::firstOrNew(
    ['name' => 'Tokyo to Sydney'],
    ['delayed' => 1, 'arrival_time' => '11:30']
);

$flight = new Flight;
$flight->name = $request->name;
$flight->save();

$flight = Flight::create([
    'name' => 'London to Paris',
]);

$flight = Flight::find(1);
$flight->name = 'Paris to London';
$flight->save();

$flight->update([
	'name' => 'Paris to London'
]);

$flight = Flight::updateOrCreate(
    ['departure' => 'Oakland', 'destination' => 'San Diego'],
    ['price' => 99, 'discounted' => 1]
);

// 通过模型实例删除
$flight = Flight::find(1);
$flight->delete();

// 通过 ID 删除
Flight::destroy(1);

Flight::destroy(1, 2, 3);

Flight::destroy(collect([1, 2, 3]));

// 通过查询构造器按条件删除
$deleted = Flight::where('active', 0)->delete();
// 删除全部
$deleted = Flight::query()->delete();

// 新增单个
$comment = new Comment(['message' => '一条新评论。']);
$post = Post::find(1);
$post->comments()->save($comment);

// 新增多个
$post = Post::find(1);
$post->comments()->saveMany([
    new Comment(['message' => '一条新评论。']),
    new Comment(['message' => '另一条新评论。']),
]);

$post = Post::find(1);
$comment = $post->comments()->create([
    'message' => '一条新评论。',
]);

$post = Post::find(1);
$post->comments()->createMany([
    ['message' => '一条新评论。'],
    ['message' => '另一条新评论。'],
]);

// 在子模型上设置外键
$account = Account::find(10);
$user->account()->associate($account);
$user->save();

// 在子模型上设置外键为 null
$user->account()->dissociate();
$user->save();

// 附加
$user = User::find(1);
$user->roles()->attach($roleId);
// 附加并更新中间表属性
$user->roles()->attach($roleId, ['expires' => $expires]);
// 附加指定 ID 并更新中间表属性
$user->roles()->attach([
    1 => ['expires' => $expires],
    2 => ['expires' => $expires],
]);

// 分离
$user->roles()->detach($roleId);
// 分离所有
$user->roles()->detach();
// 分离指定 ID
$user->roles()->detach([1, 2, 3]);

// 指定要保留的 ID
$user->roles()->sync([1, 2, 3]);
// 指定要保留的 ID 以及要保存到中间表的属性
$user->roles()->sync([1 => ['expires' => true], 2, 3]);
// 指定要保留的 ID 以及批量指定要保存到中间表的属性
$user->roles()->syncWithPivotValues([1, 2, 3], ['active' => true]);
// 指定要保留的 ID，同时不删除已有的
$user->roles()->syncWithoutDetaching([1, 2, 3]);

$user->roles()->toggle([1, 2, 3]);
$user->roles()->toggle([
    1 => ['expires' => true],
    2 => ['expires' => true],
]);