[英]Mongodb see if all items in array exist and update else insert
I have a mongo collection of tags and when the user enters an array of tags I want to do the following :我有一个 mongo 标签集合,当用户输入一组标签时,我想执行以下操作:
If a tag in the array exists, update the count If a tag in the array does not exist, insert with a count of 0如果数组中存在标签,则更新计数 如果数组中不存在标签,则插入计数为 0
I currently have :我目前有:
QuestionTags.update({'tag': {$in: tagArray}}, {$inc : {'count': +1} }, { upsert: true });
QuestionTags
is the mongoose schema for the db collection. QuestionTags
是 db 集合的猫鼬模式。
This does not seem to be working.这似乎不起作用。 I entered an array of new tags and they are not being added, and the existing tags are not being incremented.
我输入了一组新标签,但没有添加它们,也没有增加现有标签。
Is there a way to handle this without having to loop through tagArray
and make a db call for each item in the array?有没有办法处理这个而不必循环遍历
tagArray
并对数组中的每个项目进行 db 调用?
UPDATE: Changed my code to this更新:将我的代码更改为此
QuestionTags.update({'tag': {$in: req.body.tags}}, {$inc : {'count': +1} }, { upsert: true, multi: true });
QuestionTags.find({'tag' :{$nin: req.body.tags}}, function(err, newTags) {
console.log("New Tags :" + newTags);
var tagArray = [];
newTags.forEach(function(tag){
var tagObj = {
tag: tag,
count: 1
}
tagArray.push(tagObj);
});
QuestionTags.collection.insert(tagArray);
});
However, newTags
is null.但是,
newTags
为空。 QuestionTags collection is currently empty so it should not be null. QuestionTags 集合当前为空,因此不应为空。
I think you can do this in a few queries, without querying in a loop.我认为您可以在几个查询中完成此操作,而无需循环查询。
1) Update existing tags count : your query works : 1) 更新现有标签计数:您的查询有效:
QuestionTags.update({'tag': {$in: tagArray}}, {$inc : {'count': +1} },{multi: true} );
2) Find new tags : 2)查找新标签:
QuestionTags.find({},function(err, tags) {
var newTagObj = [];
// tags is originally an array of objects
// creates an array of strings (just tag name)
tags = tags.map(function(tag) {
return tag.tag;
});
// returns tags that do not exist
var newTags = tagArray.filter(function(tag) {
// The count = 1 can be done here
if (tags.indexOf(tag) < 0) {
tag.count = 1;
}
return tags.indexOf(tag) < 0;
});
// creates tag objects with a count of 1
// adds to array
// (this can be done in the previous loop)
newTags.forEach(function(tag) {
var tagObj = {
tag: tag,
count: 1
}
newTagObj.push(tagObj);
});
This will give you an array of tags that don't exist in database.这将为您提供数据库中不存在的一系列标签。
3) Insert new tags using result of 2, in the find
callback: 3) 在
find
回调中使用结果 2 插入新标签:
QuestionTags.collection.insertMany(newTagObj);
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