Day50:Python操作MongoDB文档数据库

1.Pymongo 详解

  • 安装pymongo
  pip install pymongo
  • PyMongo是驱动程序,使python程序能够使用Mongodb数据库,使用python编写而成;

  • one_insert():插入一条记录;

  • insert():插入多条记录;

  • find_one():查询一条记录,不带任何参数返回第一条记录,带参数则按条件查找返回;

  • find():查询多条记录,不带参数返回所有记录,带参数按条件查找返回;

  • count():查看记录总数;

  • create_index():创建索引;

  • update_one():更新匹配到的第一条数据;

  • update():更新匹配到的所有数据;

  • remove():删除记录,不带参表示删除全部记录,带参则表示按条件删除;

  • delete_one():删除单条记录;

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  • delete_many():删除多条记录;

2.查看数据库

from pymongo import MongoClient
connect = MongoClient(host='localhost', port=27017, username="root", password="123456")
connect = MongoClient('mongodb://localhost:27017/', username="root", password="123456")
print(connect.list_database_names())

3.插入一行document, 查询一行document,取出一行document的值

from pymongo import MongoClient
from datetime import datetime

connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)
# 获取db
test_db = connect['test']
# 获取collection
collection = test_db['students']
# 构建document
document = {"author": "Mike",  "text": "My first blog post!", "tags": ["mongodb", "python", "pymongo"], "date": datetime.now()}
# 插入document
one_insert = collection.insert_one(document=document)
print(one_insert.inserted_id)

# 通过条件过滤出一条document
one_result = collection.find_one({"author": "Mike"})
# 解析document字段
print(one_result, type(one_result))
print(one_result['_id'])
print(one_result['author'])

注意:如果需要通过id查询一行document,需要将id包装为ObjectId类的实例对象
from bson.objectid import ObjectId
collection.find_one({'_id': ObjectId('5c2b18dedea5818bbd73b94c')})

4.插入多行documents, 查询多行document, 查看collections有多少行document

from pymongo import MongoClient
from datetime import datetime
connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)

# 获取db
test_db = connect['test']

# 获取collection
collection = test_db['students']
documents = [{"author": "Mike","text": "Another post!","tags": ["bulk", "insert"], "date": datetime(2009, 11, 12, 11, 14)},
{"author": "Eliot", "title": "MongoDB is fun", "text": "and pretty easy too!", "date": datetime(2009, 11, 10, 10, 45)}]
collection.insert_many(documents=documents)

# 通过条件过滤出多条document
documents = collection.find({"author": "Mike"})

# 解析document字段
print(documents, type(documents))
print('*'*300)
for document in documents:
    print(document)
print('*'*300)
result = collection.count_documents({'author': 'Mike'})
print(result)

5.范围比较查询

from pymongo import MongoClient
from datetime import datetime

connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)

# 获取db
test_db = connect['test']

# 获取collection
collection = test_db['students']

# 通过条件过滤时间小于datetime(2019, 1,1,15,40,3) 的document
documents = collection.find({"date": {"$lt": datetime(2019, 1,1,15,40,3)}}).sort('date')

# 解析document字段
print(documents, type(documents))
print('*'*300)
for document in documents:
    print(document)

6.创建索引

from pymongo import MongoClient
import pymongo
from datetime import datetime

connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)
# 获取db
test_db = connect['test']
# 获取collection
collection = test_db['students']
# 创建字段索引
collection.create_index(keys=[("name", pymongo.DESCENDING)], unique=True)
# 查询索引
result = sorted(list(collection.index_information()))
print(result)

7.document修改

from pymongo import MongoClient
connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)

# 获取db
test_db = connect['test']

# 获取collection
collection = test_db['students']
result = collection.update({'name': 'robby'}, {'$set': {"name": "Petter"}})
print(result)
注意:还有update_many()方法

8.document删除

from pymongo import MongoClient
connect = MongoClient(host='localhost', port=27017, username="root", password="123456",)

# 获取db
test_db = connect['test']

# 获取collection
collection = test_db['students']
result = collection.delete_one({'name': 'Petter'})
print(result.deleted_count)
注意:还有delete_many()方法

9.MongoDB ODM 详解

  • MongoDB ODM 与 Django ORM使用方法类似;

  • MongoEngine是一个对象文档映射器,用Python编写,用于处理MongoDB;

  • MongoEngine提供的抽象是基于类的,创建的所有模型都是类;

# 安装mongoengine
pip install mongoengine

10.使用mongoengine创建数据库连接的参数讲解

from mongoengine import connect
conn = connect(db='test', host='localhost', port=27017, username='root', password='123456', authentication_source='admin')
print(conn)

connect(db = None,alias ='default',** kwargs );

  • db:要使用的数据库的名称,以便与connect兼容;

  • host :要连接的mongod实例的主机名;

  • port :运行mongod实例的端口;

  • username:用于进行身份验证的用户名;

  • password:用于进行身份验证的密码;

  • authentication_source :要进行身份验证的数据库;

11.mongoengine查询的方法

##################查询数据
from mongoengine import connect, \
                        Document, \
                        StringField,\
                        IntField, \
                        FloatField,\
                        ListField, \
                        EmbeddedDocumentField,\
                        DateTimeField, \
                        EmbeddedDocument
from datetime import datetime

# 嵌套文档
class Score(EmbeddedDocument):
    name = StringField(max_length=50, required=True)
    value = FloatField(required=True)

class Students(Document):
    choice =  (('F', 'female'),
               ('M', 'male'),)

    name = StringField(max_length=100, required=True, unique=True)
    age = IntField(required=True)
    hobby = StringField(max_length=100, required=True, )
    gender = StringField(choices=choice, required=True)
    # 这里使用到了嵌套文档,这个列表中的每一个元素都是一个字典,因此使用嵌套类型的字段
    score = ListField(EmbeddedDocumentField(Score))
    time = DateTimeField(default=datetime.now())

if __name__ == '__main__':
    connect(db='test', host='localhost', port=27017, username='root', password='123456', authentication_source='admin')

    first_document = Students.objects.first()

    all_document = Students.objects.all()

    # 如果只有一条,也可以使用get
    specific_document = Students.objects.filter(name='robby3')
    print(first_document.name, first_document.age, first_document.time)
    for document in all_document:
        print(document.name)
    for document in specific_document:
        print(document.name, document.age)
  • all():返回所有文档;

  • all_fields():包括所有字段;

  • as_pymongo():返回的不是Document实例 而是pymongo值;

  • average():平均值超过指定字段的值;

  • batch_size():限制单个批次中返回的文档数量;

  • clone():创建当前查询集的副本;

  • comment():在查询中添加注释;

  • count():计算查询中的选定元素;

  • create():创建新对象,返回保存的对象实例;

  • delete():删除查询匹配的文档;

  • distinct():返回给定字段的不同值列表;

12.嵌入式文档查询的方法

  • count():列表中嵌入文档的数量,列表的长度;

  • create():创建新的嵌入式文档并将其保存到数据库中;

  • delete():从数据库中删除嵌入的文档;

  • exclude(** kwargs ):通过使用给定的关键字参数排除嵌入的文档来过滤列表;

  • first():返回列表中的第一个嵌入文档;

  • get():检索由给定关键字参数确定的嵌入文档;

  • save():保存祖先文档;

  • update():使用给定的替换值更新嵌入的文档;

参考:https://www.9xkd.com/user/plan-view.html?id=2253255600

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转载自blog.csdn.net/ivenqin/article/details/89174434