[英]MongoDB find document if exist - update else - insert
我在mongodb上遇到了一些麻煩。 我的代碼:
for(var j = 0; j < arrayOfWords.length; ++j) {
var word = arrayOfWords[j];
(function(word) {
if (word.length > 2) {
async.waterfall([
function(callback) {
collection.find({'word': word}).limit(1).toArray(function(err, data) {
log.info('find');
callback(err, data[0]);
})
},
function(data, callback) {
if (typeof data != 'undefined') {
log.info('Word found: ' + data);
unigramCollection.update({'word': word}, {'$inc' : {'sequence': 1}}, function(err, result) {
callback(err, result);
});
} else {
collection.insert({'word': word, 'sequence': 1}, function(err, result) {
log.info('Insert done!' + JSON.stringify(result));
callback(err, result);
})
}
}
],
function(err, result) {
if(err) {
log.error('error: ' + err);
} else {
log.info('done!');
}
});
}
})(word);
}
我不明白為什么,但是mongoDB首先會找到所有內容,然后再進行其他所有操作。 安慰:
2014-05-31T12:27:03.112Z - info: [socket/projects.js] find
2014-05-31T12:27:03.113Z - info: [socket/projects.js] find
2014-05-31T12:27:03.113Z - info: [socket/projects.js] find
2014-05-31T12:27:03.116Z - info: [socket/projects.js] Insert done![{"word":"fhhghg","sequence":1,"_id":"5389ca979a49694e2c7ac7d2"}]
2014-05-31T12:27:03.116Z - info: [socket/projects.js] done!
2014-05-31T12:27:03.117Z - info: [socket/projects.js] Insert done![{"word":"dtrtr","sequence":1,"_id":"5389ca979a49694e2c7ac7d3"}]
2014-05-31T12:27:03.117Z - info: [socket/projects.js] done!
2014-05-31T12:27:03.117Z - info: [socket/projects.js] Insert done![{"word":"jgf","sequence":1,"_id":"5389ca979a49694e2c7ac7d4"}]
2014-05-31T12:27:03.118Z - info: [socket/projects.js] done!
如何執行以必要的順序執行操作:查找是否存在doc,更新此doc,否則插入新的doc
您可以使用mongodb upsert
來執行整個操作,而不必為每個單詞排序多個操作;
db.test.update({'word':word}, {'$inc':{'sequence':1}}, {'upsert':true})
這將通過一次操作更新一個現有單詞,或者將其插入序列1(如果尚不存在)。
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