使用 Laravel 迁移将默认值设置为 NULL
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/27558713/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Set default to NULL with laravel migration
提问by James Stott
I am adding a field to a table in a migration that I wish to allow to be NULL but also I wish for it to default to NULL. What do I place in the default method? I fear that putting "NULL"in will attempt to place a string of NULLin which I obviously don't want. Please help :)
我正在向迁移中的表添加一个字段，我希望允许为 NULL，但也希望它默认为 NULL。我在默认方法中放置什么？我担心放入"NULL"会尝试放置一串NULL我显然不想要的字符串。请帮忙 ：）
Schema::table('item_categories', function(Blueprint $table)
{
$table->integer('parent_item_category_id')->unsigned()->nullable()->default($what_to_put here);
});
回答by James Stott
When you use the nullable()method on a field, that field will default to NULL.
当您nullable()在字段上使用该方法时，该字段将默认为 NULL。
