Laravel 数据库操作 Eloquent ORM

发布时间：2020-12-14 19:59:01 所属栏目：大数据来源：网络整理

导读：div class="cnblogs_code" 建立模型 use IlluminateDatabaseEloquentModel; class Student extends Model { //指定表名默认模型名的复数 protected $table='student'; //指定主键默认主键为IDprotected $primaryKey='id';//指定允许批量赋值的字段pro

建立模型

use IlluminateDatabaseEloquentModel;

class Student extends Model
{
//指定表名默认模型名的复数
protected $table='student';

//指定主键 默认主键 为ID
protected  $primaryKey='id';

//指定允许批量赋值的字段
protected $fillable=['name','age'];
//指定不允许批量赋值的字段
protected $guarded=[];

//是否维护时间戳  默认维护
//$timestamps=falst 不维护
public $timestamps=true;

//维护时间的时候保存时间戳
protected function getDateFormat()
{
    return time(); // TODO: Change the autogenerated stub
}

//查询的时候返回时间戳
protected function asDateTime($value)
{

// return parent::asDateTime($value); // TODO: Change the autogenerated stub
return $value;
}
}

ORM 查询

=Student::

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;根据主键查询 查询一条数据</span>
    <span style="color: #800080"&gt;$student</span>=Student::find(2<span style="color: #000000"&gt;);
    dd(</span><span style="color: #800080"&gt;$student</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;findOrFail() 根据主键查询 如果没有查到 报错</span>
    <span style="color: #800080"&gt;$student</span>=Student::findOrFail(2<span style="color: #000000"&gt;);
    dd(</span><span style="color: #800080"&gt;$student</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;get() 查询所有数据</span>
    <span style="color: #800080"&gt;$students</span>=Student::<span style="color: #000000"&gt;get();
    dd(</span><span style="color: #800080"&gt;$students</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;first() 查询第一条</span>
    <span style="color: #800080"&gt;$students</span>=Student::where('id','>','1')->orderBy('age','desc')-><span style="color: #000000"&gt;first();
    dd(</span><span style="color: #800080"&gt;$students</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;chunk() 每次查询一定条数 </span>
    Student::chunk(2,<span style="color: #0000ff"&gt;function</span>(<span style="color: #800080"&gt;$students</span><span style="color: #000000"&gt;){
        </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$students</span><span style="color: #000000"&gt;);
    });

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;聚合函数
    //count() 条数</span>
    <span style="color: #800080"&gt;$num</span> = Student::<span style="color: #008080"&gt;count</span><span style="color: #000000"&gt;();
    </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$num</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;max() 查询最大值</span>
    <span style="color: #800080"&gt;$max</span>=Student::where('id',1)-><span style="color: #008080"&gt;max</span>('age'<span style="color: #000000"&gt;);
    </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$max</span>);</pre>

添加

=->name='vbb'->age=34=->

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;create()</span>
    <span style="color: #800080"&gt;$rs</span>=Student::<span style="color: #000000"&gt;create([
        </span>'name'=>'momo','age'=>23<span style="color: #000000"&gt;
    ]);
    dd(</span><span style="color: #800080"&gt;$rs</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;firstOrCreate()以属性查询数据 如果没有 新建数据</span>
    <span style="color: #800080"&gt;$rs</span>=Student::<span style="color: #000000"&gt;firstOrCreate(
        [</span>'name'=>'vbb4'<span style="color: #000000"&gt;]
    );

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;firstOrNew() 以属性查询数据 如果没有 新建实例 如果想保存调用save()</span>
    <span style="color: #800080"&gt;$rs</span>=Student::<span style="color: #000000"&gt;firstOrNew(
        [</span>'name'=>'vbb4'<span style="color: #000000"&gt;]
    );
    </span><span style="color: #800080"&gt;$bool</span>=<span style="color: #800080"&gt;$rs</span>-><span style="color: #000000"&gt;save();

    dd(</span><span style="color: #800080"&gt;$rs</span>);</pre>

更新

=Student::find(2->age=2=->(

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;批量更新</span>
    <span style="color: #800080"&gt;$num</span>=Student::where('id',5)-><span style="color: #000000"&gt;update(
        [</span>'age'=>41<span style="color: #000000"&gt;]
    );
    </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$num</span>);</pre>

删除

=Student::find(2=->(

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;通过主键删除</span>
    <span style="color: #800080"&gt;$num</span>=Student::destroy(3,4,5<span style="color: #000000"&gt;);
    </span><span style="color: #800080"&gt;$num</span>=Student::destroy([3,5<span style="color: #000000"&gt;]);
    </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$num</span><span style="color: #000000"&gt;);

    </span><span style="color: #008000"&gt;//</span><span style="color: #008000"&gt;删除指定条件</span>
    <span style="color: #800080"&gt;$num</span>=Student::where('id',7)-><span style="color: #000000"&gt;delete();
    </span><span style="color: #008080"&gt;var_dump</span>(<span style="color: #800080"&gt;$num</span>);</pre>

（编辑：李大同）

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