這篇文章為大家?guī)砹岁P(guān)於Laravel的相關(guān)知識，其中主要跟大家介紹Laravel Eloquent模型中樂觀鎖的實現(xiàn)，有代碼示例，感興趣的朋友下面一起來看一下吧，希望對大家有幫助。

在app/Utils/Traits目錄下建立OptimisticLockTrait.php，程式碼如下：

namespace?App\Utils\Traits;use?Illuminate\Database\Eloquent\Builder;trait?OptimisticLockTrait{

????/**
?????*?@var?array?$optimisticConditions
?????*?@var?array?$bindings
?????*/
????protected?$optimisticConditions,?$bindings;
????/**
?????*?@var?string?$optimisticConditionRaw
?????*/
????protected?$optimisticConditionRaw;

????/**
?????*?save?時增加樂觀鎖條件
?????*?@param?Builder?$builder
?????*/
????protected?function?performUpdate(Builder?$builder)
????{
????????if?(!empty($this->optimisticConditions))?{
????????????foreach?($this->optimisticConditions?as?$field?=>?$value)?{
????????????????if?(is_array($value))?{
????????????????????$count?=?count($value);
????????????????????if?($count?>=?3)?{
????????????????????????switch?(strtoupper($value[1]))?{
????????????????????????????case?'IN':
????????????????????????????????$builder->whereIn($value[0],?$value[2]);
????????????????????????????????break;
????????????????????????????case?'NOT?IN':
????????????????????????????????$builder->whereNotIn($value[0],?$value[2]);
????????????????????????????????break;
????????????????????????????case?'BETWEEN':
????????????????????????????????$builder->whereBetween($value[0],?$value[2]);
????????????????????????????????break;
????????????????????????????case?'NOT?BETWEEN':
????????????????????????????????$builder->whereNotBetween($value[0],?$value[2]);
????????????????????????????????break;
????????????????????????????default:
????????????????????????????????$builder->where($value[0],?$value[1],?$value[2]);
????????????????????????}
????????????????????}?else?{
????????????????????????$builder->where($value);
????????????????????}
????????????????}?else?{
????????????????????$builder->where($field,?$value);
????????????????}
????????????}
????????}
????????//?原始條件注入
????????if?($this->optimisticConditionRaw)
????????????$builder->whereRaw($this->optimisticConditionRaw,?$this->bindings);

????????return?$this->clearOptimistic()->perFormUpdating($builder);

????}


????/**
?????*?updating?with?optimistic
?????*
?????*?@param?Builder?$builder
?????*?@return?bool
?????*/
????protected?function?perFormUpdating(Builder?$builder)
????{

????????//?If?the?updating?event?returns?false,?we?will?cancel?the?update?operation?so
????????//?developers?can?hook?Validation?systems?into?their?models?and?cancel?this
????????//?operation?if?the?model?does?not?pass?validation.?Otherwise,?we?update.
????????if?($this->fireModelEvent('updating')?===?false)?{
????????????return?false;
????????}

????????//?First?we?need?to?create?a?fresh?query?instance?and?touch?the?creation?and
????????//?update?timestamp?on?the?model?which?are?maintained?by?us?for?developer
????????//?convenience.?Then?we?will?just?continue?saving?the?model?instances.
????????if?($this->usesTimestamps())?{
????????????$this->updateTimestamps();
????????}

????????//?Once?we?have?run?the?update?operation,?we?will?fire?the?"updated"?event?for
????????//?this?model?instance.?This?will?allow?developers?to?hook?into?these?after
????????//?models?are?updated,?giving?them?a?chance?to?do?any?special?processing.
????????$dirty?=?$this->getDirty();
????????$res?=?0;
????????if?(count($dirty)?>?0)?{
????????????$res?=?$this->setKeysForSaveQuery($builder)->update($dirty);

????????????$this->syncChanges();

????????????$this->fireModelEvent('updated',?false);
????????}
????????return?!empty($res);
????}

????//?清除樂觀鎖條件
????function?clearOptimistic()
????{
????????$this->optimisticConditions?=?null;
????????$this->optimisticConditionRaw?=?null;
????????return?$this;
????}


????//?設(shè)置樂觀鎖條件字段名列表
????function?setOptimistic(array?$optimisticConditions)
????{
????????$this->optimisticConditions?=?$optimisticConditions;
????????return?$this;
????}

????//?設(shè)置樂觀鎖原始條件字段名列表
????function?setOptimisticRaw(string?$optimisticConditionRaw,?array?$bindings?=?[])
????{
????????$this->optimisticConditionRaw?=?$optimisticConditionRaw;
????????$this->bindings?=?$bindings;
????????return?$this;
????}}

樂觀鎖定使用說明

#1、在模型中(Models)或模型父類別使用

/**
*?App\Models\BaseModel
*?@mixin?\Eloquent
*?@method?static?\Illuminate\Database\Eloquent\Builder|BaseModel?newModelQuery()
*?@method?static?\Illuminate\Database\Eloquent\Builder|BaseModel?newQuery()
*?@method?static?\Illuminate\Database\Eloquent\Builder|BaseModel?query()
*/class?BaseModel?extends?Model{
??use?OptimisticLockTrait;}

2、使用方法：

?$ord?=?Order::find(1);
?$ord->payment_status?=?1;
?if(!$model->setOptimistic(['payment_status'?=>?0]))->save())
???throws?new?Exception('訂單已付過款了');

或使用原始SQL方式:

?$ord?=?Order::find(1);
?$ord->payment_status?=?1;
?if(!$model->setOptimisticRaw('payment_status?=??',[1]))->save())
???throws?new?Exception('訂單已付過款了');

如果相同物件小涉及到多次更新，則可以清除鎖定條件

$ord->clearOptimistic();

以上就是樂觀鎖的實作方式，在實際開發(fā)中比較常用也很有必要。

推薦學(xué)習(xí)：《laravel影片教學(xué)》

以上是Laravel Eloquent模型中樂觀鎖的實現(xiàn)的詳細內(nèi)容。更多資訊請關(guān)注PHP中文網(wǎng)其他相關(guān)文章！