mongoDB_use.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
'''
pyMongo的使用方法
'''
import pymongo
import datetime


def get_db():
    # 建立连接
    try:
        client = pymongo.MongoClient(host="10.2.25.10", port=27017)
    except Exception as e:
        print(str(e))
    db = client['example']
    # 或者 db = client.example
    print(db)
    return db


def get_collection(db):
    # 选择集合（mongo中collection和database都是延时创建的）
    # 创建一个表，表明为informations,例如： db.informations.insert()
    coll = db['informations']
    print(db.collection_names())
    return coll


def insert_one_doc(db):
    # 插入一个document
    coll = db['informations']
    information = {"name": "liujian", "age": "25"}
    information_id = coll.insert(information)
    print(information_id)


def insert_multi_docs(db):
    # 批量插入documents,插入一个数组
    coll = db['informations']
    information = [{"name": "xiaoming", "age": "25"},
                   {"name": "xiaoqiang", "age": "24"}]
    information_id = coll.insert(information)
    print(information_id)


def get_one_doc(db):
    # 有就返回一个，没有就返回None
    coll = db['informations']
    print(coll.find_one())  # 返回第一条记录
    print(coll.find_one({"name": "liujian"}))
    print(coll.find_one({"name": "none"}))


def get_one_by_id(db):
    # 通过objectid来查找一个doc
    coll = db['informations']
    obj = coll.find_one()
    obj_id = obj["_id"]
    print("_id 为ObjectId类型，obj_id:" + str(obj_id))

    print(coll.find_one({"_id": obj_id}))
    # 需要注意这里的obj_id是一个对象，不是一个str，使用str类型作为_id的值无法找到记录
    print("_id 为str类型 ")
    print(coll.find_one({"_id": str(obj_id)}))
    # 可以通过ObjectId方法把str转成ObjectId类型
    from bson.objectid import ObjectId

    print("_id 转换成ObjectId类型")
    print(coll.find_one({"_id": ObjectId(str(obj_id))}))


def get_many_docs(db):
    # mongo中提供了过滤查找的方法，可以通过各种条件筛选来获取数据集，还可以对数据进行计数，排序等处理
    coll = db['informations']
    # ASCENDING = 1 升序;DESCENDING = -1降序;default is ASCENDING
    for item in coll.find().sort("age", pymongo.DESCENDING):
        print(item)

    count = coll.count()
    print("集合中所有数据 %s个" % int(count))

    # 条件查询
    count = coll.find({"name": "liujian"}).count()
    print("liujian: %s" % count)


def clear_all_datas(db):
    # 清空一个集合中的所有数据
    db["informations"].remove()


if __name__ == '__main__':
    db = get_db()
    my_collection = get_collection(db)
    post = {"author": "Mike", "text": "My first blog post!", "tags": ["mongodb", "python", "pymongo"],
            "date": datetime.datetime.utcnow()}
    # 插入记录
    my_collection.insert(post)
    insert_one_doc(db)
    # 条件查询
    print(my_collection.find_one({"x": "10"}))
    # 查询表中所有的数据
    for iii in my_collection.find():
        print(iii)
    print(my_collection.count())
    my_collection.update({"author": "Mike"},
                         {"author": "liujian", "text": "My first blog post!", "tags": ["mongodb", "python", "pymongo"],
                          "date": datetime.datetime.utcnow()})
    for jjj in my_collection.find():
        print(jjj)
    get_one_doc(db)
    get_one_by_id(db)
    get_many_docs(db)
    # clear_all_datas(db)
    clear_all_datas(db)