如何找到2个索引数组与关联数组作为子节点的交集和并集？

The scenario is this. I have an array of items, in this format:

$a = [
    ['name' => 'John'],
    ['name' => 'Doe']
];

In a further update, I get a new array with some values removed while some added. It looks like this:

$b = [
    ['name' => 'John'],
    ['name' => 'Smith']
];

How would I calculate the union and the difference of these 2, so that I can remove Doe from my database and add Smith since my new data has these changes?