如何使用架构生成器添加虚拟列? [英] How to add a virtual column with the schema builder?

问题描述

我正在创建一个这样的表，

I'm creating a table like this,

Schema::create('booking_segments', function (Blueprint $table) {
    $table->increments('id');

    $table->datetime('start')->index();
    $table->integer('duration')->unsigned();
    $table->string('comments');
    $table->integer('booking_id')->unsigned();
    $table->foreign('booking_id')->references('id')->on('bookings')->onDelete('cascade');
});

但是我想增加一列.在原始SQL中看起来像这样:

But I want to add one extra column. It looks like this in raw SQL:

ALTER TABLE booking_segments ADD COLUMN `end` DATETIME AS (DATE_ADD(`start`, INTERVAL duration MINUTE)) PERSISTENT AFTER `start`

如何在迁移中添加它?我还需要在其上创建一个索引.

How can I add it in my migration? I will also need to create an index on it.

推荐答案

我知道这是一个老问题，但是自Laravel 5.3起，就有一种方法可以使用架构生成器来实现，所以我想将其放在此处完整性.

I know this is an old question, but there is a way to do it using the schema builder since Laravel 5.3, so I thought I would put it here for completeness.

您可以使用laravel 5.3 列修饰符 virtualAs或storedAs.

You can use laravel 5.3 column modifiers virtualAs or storedAs.

因此，要创建一个虚拟的生成的列以在每次查询时进行计算，您将像这样创建该列:

So, to create a virtual generated column to be computed at every query you would create the column like this:

$table->dateTime('created_at')->virtualAs( 'DATE_ADD(`start`, INTERVAL duration MINUTE)' );

要创建存储的生成的列，您可以改成这样的列:

To create a stored generated column you would create the column like this instead:

$table->dateTime('created_at')->storedAs( 'DATE_ADD(`start`, INTERVAL duration MINUTE)' );

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