本文实例讲述了Laravel框架EloquentORM简介、模型建立及查询数据操作。分享给大家供大家参考
本文实例讲述了Laravel框架Eloquent ORM简介、模型建立及查询数据操作。分享给大家供大家参考，具体如下：
注：以下知识点可能有不全面之处，望见谅
NO.1Eloquent ORM简介
Laravel所自带的Eloquent ORM是一个优美、简洁的ActiveRecord实现，用来实现数据库操作 每个数据表都有与之相对应的“模型（Model）”用于和数据交互
NO.2模型的建立
最基础的模型代码如下:
namespace App;
use Illuminate\Database\Eloquent\Model;
class Student extends Model
{
//指定表名
protected $table = 'student';
//指定id
protected $primaryKey = 'id';
}
将他创建于app目录下，命名为Student.php
NO.3查询数据
首先在查询之前，我先让你们看一下我的数据库
数据如上，然后查询
1.all方式
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$students = Student::all();
dd($students);
}
}
显示数据库里的所有数据
2.find方式
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$students = Student::find(1);
dd($students);
}
}
查找指定数据
3.findOrFail方式
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$students = Student::findOrFail(1);
dd($students);
}
}
如果他没查到指定的数据，那么他会报错，而find若是没有查到该函数，只会弹出一个null
4.查询构造器的使用
- 1.get方式使用
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$students = Student::get();
dd($students);
}
}
他会得到一个完整的数据信息，和原本的意义没有区别
- 2.first方式使用
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::where('id','>',1)
->orderBy('age','desc')
->first();
dd($student);
}
}
当id大于一的时候，获取一个最大值的age
- 3.where方式使用
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::where('id','>',1)
->get();
dd($student);
}
}
- 4.chunk方式使用
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::chunck(2,function($student){
var_dump($student);
});
}
}
5.聚合函数的使用
- 1.count函数
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::count();
dd($student);
}
}
- 2.max函数
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::max('age');
dd($student);
}
}
- 3.min函数
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::min('age');
dd($student);
}
}
- 4.avg函数
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::avg('age');
dd($student);
}
}
- 5.sum函数
代码如下:
namespace App\Http\Controllers;
use App\Student;
use Illuminate\Support\Facades\DB;
class StudentController extends Controller
{
public function orm1()
{
$student = Student::sum('age');
dd($student);
}
}