使用 DB::raw 表达式的带有 POINT/POLYGON 等的 Laravel 模型
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Laravel model with POINT/POLYGON etc. using DB::raw expressions
提问by preyz
I have some models that use geospatial fields like POINT, POLYGONor MULTIPOLYGON. I would like to tell my model to process these attributes in a special way, for me to get the desired model attributes set.
我有一些使用地理空间字段的模型，例如POINT,POLYGON或MULTIPOLYGON。我想告诉我的模型以一种特殊的方式处理这些属性，以便我获得所需的模型属性集。
Example:
Every regular Model::find()or other Eloquent method should apply some custom code before storing or after retrieving a database value.
示例：每个常规Model::find()或其他 Eloquent 方法都应该在存储之前或检索数据库值之后应用一些自定义代码。
$area->surfaceis a POLYGONfield in MySQL, but in my model class I would like to handle $area->surfareas an array of points.
$area->surface是POLYGONMySQL 中的一个字段，但在我的模型类中，我想$area->surfare作为点数组处理。
On SELECTI would therefore like to 1) fetch the value using a raw expression to get a text representation of the value, and 2) go through some custom PHP code to convert the WKT string into an array.
在SELECT因此，我要像1）使用原始表达式来获取值的文本表示获取值，和2）通过一些自定义的PHP代码到WKT字符串转换成一个数组。
On INSERT/UPDATEI would like to take the attribute value (an array) and 1) convert it into a WKT string, whereafter 2) it's written to the databse using a DB raw statement that stores the value.
在INSERT/UPDATE我想借属性值（阵列）和1）将其转换为WKT字符串，此后2）它采用了一块DB原始声明店该值的写入DATABSE。
I'd like to set this on a field-basis, not as special get/set functions for each field, and not in the controllers - because I have many geosptial fields.
我想在现场设置它，而不是为每个字段设置特殊的获取/设置功能，而不是在控制器中 - 因为我有很多地理空间字段。
Is there a way to achieve this in Laravel?
有没有办法在 Laravel 中实现这一目标？
(A more abstract version of the same question, is how I can create code that manipulates attribute values for the actual SQL queries, rather than just some value-based manipulation via mutators & accessors)
（同一问题的一个更抽象的版本，是我如何创建代码来操作实际 SQL 查询的属性值，而不仅仅是通过修改器和访问器进行一些基于值的操作）
UPDATE:Looking deeper into the Laravel Doc and API, I found that maybe the Eloquent::newQuery()method is what I need to manipulate? Would that be used for any query regardless if SELECT, INSERTor UPDATE?
更新：深入了解 Laravel Doc 和 API，我发现也许该Eloquent::newQuery()方法是我需要操作的？无论 if SELECT,INSERT还是UPDATE?
回答by preyz
We have now solved this generically for all models by extending our base model with the following functionaly:
我们现在通过使用以下功能扩展我们的基本模型，为所有模型一般地解决了这个问题：
- We define an array of attributes that hold geometric data.
- We decide on a per-model-basis if we want this to be auto-loaded as text.
- We change the default query builder to select the geometry attributes as text from the database.
- 我们定义了一组保存几何数据的属性。
- 如果我们希望将其作为文本自动加载，我们会根据每个模型来决定。
- 我们更改默认查询构建器以从数据库中选择几何属性作为文本。
Here is an excerpt from the base model we now use:
以下是我们现在使用的基本模型的摘录：
/**
* The attributes that hold geometrical data.
*
* @var array
*/
protected $geometry = array();
/**
* Select geometrical attributes as text from database.
*
* @var bool
*/
protected $geometryAsText = false;
/**
* Get a new query builder for the model's table.
* Manipulate in case we need to convert geometrical fields to text.
*
* @param bool $excludeDeleted
* @return \Illuminate\Database\Eloquent\Builder
*/
public function newQuery($excludeDeleted = true)
{
if (!empty($this->geometry) && $this->geometryAsText === true)
{
$raw = '';
foreach ($this->geometry as $column)
{
$raw .= 'AsText(`' . $this->table . '`.`' . $column . '`) as `' . $column . '`, ';
}
$raw = substr($raw, 0, -2);
return parent::newQuery($excludeDeleted)->addSelect('*', DB::raw($raw));
}
return parent::newQuery($excludeDeleted);
}
回答by marcanuy
If mutators and accessor does not fit your needs, you can manipulate those attributes with Model Events.
如果 mutator 和 accessor 不符合您的需求，您可以使用Model Events操作这些属性。
Then you can execute code when some of the Eloquent events are fired: creating, created, updating, updated, saving, saved, deleting, deleted, restoring, restored.
然后你可以在一些 Eloquent 事件被触发时执行代码：创建、创建、更新、更新、保存、保存、删除、删除、恢复、恢复。
回答by Cyber
For all who use postgres database, laravel-postgiscan be use for geometric data
对于所有使用 postgres 数据库的人，laravel-postgis可以用于几何数据
