0
假设我有以下MongoDB的集合,我想找到他们ratings.by
为ijk
的所有文件,并更新其评级至6在MongoDB中,如何查找和更新特定的数组元素?
换句话说,更新{ by: "ijk", rating: 4 }
到{ by: "ijk", rating: 6 }
。问题是我不知道这样的数组元素的索引。
{
_id: 1,
item: "TBD",
stock: 0,
info: { publisher: "1111", pages: 430 },
tags: [ "technology", "computer" ],
ratings: [ { by: "ijk", rating: 4 }, { by: "lmn", rating: 5 } ],
reorder: false
}
我的问题:我应该怎么写的db.collection.update()
功能?这是我的失败尝试:
db.collection.update({
ratings.by: {
$elemMatch: {
$eq: 'ijk'
}
}
}, {
$set: {
// don't know which index to set. How should I modify this line?
ratings.rating: 6
}
}, {
multi: true
});