先理解几个概念:
StdClass 对象 => 基础的对象
Eloquent 模型对象(Model 对象) => 和模型相关的类对象
Eloquent 集合 => 可以简单理解为对象数组，里面的每一个元素都是一个Model 对象
DB Facades
1, $users = DB::table('users')->get(); 返回值：数组结果，其中每一个结果都是 StdClass
2, $user = DB::table('users')->first(); 返回值：单个 StdClass 实例
Eloquent
1, $user = User::first(); 返回值：Eloquent 对象
2, $user = User::find(); 返回值：Eloquent 对象
3, $users = User::get(); 返回值：Eloquent 集合
4, $users = User::all(); 返回值：Eloquent 集合
5, $user = User::create($data); 返回值：Eloquent 对象
6, $user = new User();
$user->name = "admin"
$user->save();
返回值：Eloquent 对象
7, $result = User::insert($data); 返回值：bool
8, $result = $user->delete(); 返回值：bool
9, $count = User::destroy([1, 2]); 返回值：删除记录数
10, $count = User::where('id', '>', 1)->delete(); 返回值：删除记录数
11, $count = User::where('id', '>', 10)->update(['status' => 1]);返回值：更新记录数
12, $count = User::where('id', '>', 10)->increment('age', 1); 返回值：更新记录数
