我最近开始使用Laravel 5作为一个框架。到目前为止，一切都很顺利，能和它一起工作真是太好了。然而，目前我在Eloquent的一款车型上遇到了一些麻烦。
数据库表reports具有以下模式：
| id | group_id | score | ... |
group_id是引用groups表的外键。该表的主键是id和group_id的组合。id也不是自动增加的，因为它是一个外部id，我正在使用它来简化内部处理。
每个外部id可以为我的每个组出现一次，并且每个组都有不同的分数，因此是复合主键。
当访问我的某个页面时，我想从外部数据源获取最新的记录，并将它们与相应的数据库行进行匹配。如果它们不存在，我想创建它们。
我目前对这条路线的编码是：
public function showReports ($id)
{
$group = Group::findOrFail($id);
foreach ($group->getLatestReports(20) as $reportElement)
{
$report = Report::find($reportElement['id']);
if (is_null($report))
{
$report = new Report;
// Fill values ...
$report->save();
}
}
}
这显然没有如预期的那样工作，因为它只查找id
（::find($reportElement['id'])），而不是用于group_id。和往常一样，我的问题答案可能非常简单，但我现在似乎找不到。
Model::find仅适用于单列键。您可以向它传递一个数组，但这只会使它查找多行。
您需要将两个where链接在一起才能进行查询：
$report = Report::where('id', '=', $reportElement['id'])
->where('group_id', '=', $group->id)
->first();
您可以创建一个Trait MutiPrimaryKey，然后扩展getKey并查找方法：1）在App''Classes''Database中创建以下文件MultiPrimaryKey.php
<?php
namespace App'Classes'Database;
use Illuminate'Database'Eloquent'Builder;
trait MultiPrimaryKey {
protected function setKeysForSaveQuery(Builder $query)
{
$keys = $this->getKeyName();
if(!is_array($keys)){
return parent::setKeysForSaveQuery($query);
}
foreach($keys as $keyName){
$query->where($keyName, '=', $this->getKeyForSaveQuery($keyName));
}
return $query;
}
protected function getKeyForSaveQuery($keyName = null)
{
if(is_null($keyName)){
$keyName = $this->getKeyName();
}
if (isset($this->original[$keyName])) {
return $this->original[$keyName];
}
return $this->getAttribute($keyName);
}
public function getKey()
{
$keys = $this->getKeyName();
if(!is_array($keys)){
return parent::getKey();
}
$pk = [];
foreach($keys as $keyName){
$pk[$keyName] = $this->getAttribute($keyName);
}
return $pk;
}
public function find($id, $columns = ['*'])
{
if (is_array($id) || $id instanceof Arrayable) {
$out = null;
foreach ($id as $key => $value) {
//echo "{$key} => {$value} ";
if ($out == null)
{
$out = $this->where($key, $value);
}
else
{
$out = $out->where($key, $value);
}
}
return $out->first($columns);
}
return $this->whereKey($id)->first($columns);
}
}
然后您必须为自定义关系进行分类：2） 在App''Classes''Database中创建以下文件HasMultiPKRelationships.php
<?php
namespace App'Classes'Database;
use App'Classes'Database'Eloquent'Relations'BelongsToMultiPK;
use Illuminate'Database'Eloquent'Builder;
use Illuminate'Database'Eloquent'Relations'BelongsTo;
trait HasMultiPKRelationships {
public function belongsTo($related, $foreignKey = null, $ownerKey = null, $relation = null)
{
if ($relation === null) {
$relation = $this->guessBelongsToRelation();
}
$instance = $this->newRelatedInstance($related);
if ($foreignKey === null) {
$foreignKey = Str::snake($relation) . '_' . $instance->getKeyName();
}
$ownerKey = $ownerKey ?: $instance->getKeyName();
if ( is_array($ownerKey))
{
return new BelongsToMultiPK($instance->newQuery(), $this, $foreignKey, $ownerKey, $relation);
}
else
{
return new BelongsTo($instance->newQuery(), $this, $foreignKey, $ownerKey, $relation);
}
}
}
然后，您需要自定义BelongsTo 3）在App''Classes''Database''Eloquent''Relations中创建以下文件BelongsToMultiPK.php
<?php
namespace App'Classes'Database'Eloquent'Relations;
use Illuminate'Database'Eloquent'Relations'BelongsTo;
use Illuminate'Database'Eloquent'Model;
use Illuminate'Database'Eloquent'Builder;
use Illuminate'Database'Eloquent'Collection;
use Illuminate'Database'Eloquent'Relations'Concerns'SupportsDefaultModels;
class BelongsToMultiPK extends BelongsTo
{
public function __construct(Builder $query, Model $child, $foreignKey, $ownerKey, $relation)
{
parent::__construct($query, $child, $foreignKey, $ownerKey, $relation);
}
public function addConstraints()
{
if (static::$constraints) {
// For belongs to relationships, which are essentially the inverse of has one
// or has many relationships, we need to actually query on the primary key
// of the related models matching on the foreign key that's on a parent.
$table = $this->related->getTable();
if (! is_array($this->ownerKey) )
{
$this->query->where($table.'.'.$this->ownerKey, '=', $this->child->{$this->foreignKey});
}
else
{
foreach ($this->ownerKey as $key)
{
$this->query->where($table.'.'.$key, '=', $this->child->{$this->foreignKey}[$key]);
}
}
}
}
}