检查 Laravel 模型表中是否存在列，然后应用条件
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Check if column exist in Laravel model's table and then apply condition
提问by Niklesh Raut
Current Situation: We are creating new database for new registration.
当前情况：我们正在为新注册创建新数据库。
Problem: If any changes done in database migration we need to handle it for previously created database. Or run that migration for each previously created database.
问题：如果在数据库迁移中进行了任何更改，我们需要为以前创建的数据库处理它。或者为每个以前创建的数据库运行该迁移。
If we run migration for each database no problem.
如果我们为每个数据库运行迁移没问题。
Question: how to check database table has column for which we are applying condition in query.
问题：如何检查数据库表是否有我们在查询中应用条件的列。
Currently I need to fire two queries first for first row and check the existence of that column and then apply condition in where clause. like below
目前我需要首先为第一行触发两个查询并检查该列是否存在，然后在 where 子句中应用条件。像下面
$firstRow = Model::first();
if(isset($firstRow->is_splited)){
$records = Model::where('is_splited',0)->get(); // this will give error if I don't check column existence for previously created database.
}else{
$records = Model::all();
}
Is there any way to achieve in one query. Or any better way to do it ?
有什么办法可以在一个查询中实现。或者有什么更好的方法来做到这一点？
Thanks for your time and suggestion.
感谢您的时间和建议。
回答by Niklesh Raut
@DigitalDrifter gave an idea to use Schemaclass so I just tried like this
@DigitalDrifter 提出了一个使用Schema类的想法，所以我只是尝试这样
I Include Schemaclass
我包括Schema类
use Illuminate\Support\Facades\Schema;
And check column by using Schemaclass, and it also works
并通过使用Schema类检查列，它也有效
$isColExist = Schema::connection("connection_name")->hasColumn('table_name','is_splited');
$q = Acquire::with("block");
if($isColExist){
$q->where('is_splited',0);
}
$records = $q->get();
回答by DigitalDrifter
You can do the following to get an array of Column classes:
您可以执行以下操作来获取 Column 类的数组：
$columns = $model->getConnection()->getDoctrineSchemaManager()->getColumns();
There's also getColumnListingand hasColumn.
回答by wheelmaker
Updated solution working in 5.8
在 5.8 中工作的更新解决方案
if ($object->getConnection()
->getSchemaBuilder()
->hasColumn($object->getTable(), 'column_name')) {
// required update here
}
This solution only requires an $object and a 'column_name' to work. The connection and table names are derived from the object itself.
此解决方案只需要 $object 和 'column_name' 即可工作。连接和表名是从对象本身派生的。
