All about MongoDB

Basic

db.createCollection('name') db.collectionName.find() db.collectionName.find({'uid': id}) db.collectionName.find().count() db.collectionName.insert({'uid': id})

批量转换string field为float

var cursor = db.collection.find();
while (cursor.hasNext()) {
    var doc = cursor.next();
    db.collection.update(
        {_id:doc._id}, 
        {$set: {
            field: parseFloat(doc.field)
        }
    });
}

查找字段重复的document

check_duplicate_document.js

var m = function () {
    emit(this.field, 1);
}
var r = function (key, values) {
    return Array.sum(values);
}
res = db.collection.mapReduce(m, r, { out : "tmp_collection" });

mongo db check_duplicate_document.js

db.tmp_collection.find({value: {$gt: 1}})

导入导出

mongoexport --host biz-mongo3 -u biz -p biz77net --port 13000 --db biz --collection eb_tuitui_data --out eb_tuitui_data.json
mongoimport --host biz-mongo3 -u biz -p biz77net --port 13000 --db biz --collection eb_tuitui_data_local --file eb_tuitui_data_local.json