Laravel 5.2时间戳

Actually the Schema Builder's timestamps method creates nullable timestamp columns by design since Laravel 5.2. The nullableTimestamps method is just a synonym which is more explicit as to how the timestamps are created, and all it does is call the timestamps method internally.

So if you need timestamp fields that are not nullable, then you need to manually create them. Also for the created_at column to be populated automatically with the current timestamp by MySQL, it needs a default values. So this:

$table->timestamps();

Should be replaced with this:

$table->dateTime('created_at')->default(DB::raw('CURRENT_TIMESTAMP'));
$table->dateTime('updated_at')->nullable();

For versions older that MySQL 5.6.5 where DATETIME columns cannot have a default value, a TIMESTAMP column can be used instead:

$table->timestamp('created_at')->default(DB::raw('CURRENT_TIMESTAMP'));

虽然，如果您使用的是Eloquent，则除了created_at创建模型条目时始终填充的列之外，其他列也应该是，nullable因为它们只有在更新或软删除时才会获得分配的值。