Python中怎么操作MongoDB文档数据库-创新互联
Python中怎么操作MongoDB文档数据库,相信很多没有经验的人对此束手无策,为此本文总结了问题出现的原因和解决方法,通过这篇文章希望你能解决这个问题。
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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;
2.Pymongo 方法
insert_one()
: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;delete_many()
:删除多条记录;
3.Pymongo 中的操作
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())
获取数据库实例
test_db = connect['test']
获取collection实例
collection = test_db['students']
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')})
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)
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": {"$lt": datetime(2019, 1,1,15,40,3)}}).sort('date') # 解析document字段 print(documents, type(documents)) print('*'*300) for document in documents: print(document)
创建索引
from pymongo import MongoClient import pymongo from datetime import datetime connect = MongoClient(host='localhost', port=27017, username="root", password="123456",) # 获取db test_db = connect['test'] # 获取collection collection = test_db['students'] # 创建字段索引 collection.create_index(keys=[("name", pymongo.DESCENDING)], unique=True) # 查询索引 result = sorted(list(collection.index_information())) print(result)
document修改
from pymongo import MongoClient connect = MongoClient(host='localhost', port=27017, username="root", password="123456",) # 获取db test_db = connect['test'] # 获取collection collection = test_db['students'] result = collection.update({'name': 'robby'}, {'$set': {"name": "Petter"}}) print(result) 注意:还有update_many()方法
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
4.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
mongoengine使用的字段类型
BinaryField BooleanField ComplexDateTimeField DateTimeField DecimalField DictField DynamicField EmailField EmbeddedDocumentField EmbeddedDocumentListField FileField FloatField GenericEmbeddedDocumentField GenericReferenceField GenericLazyReferenceField GeoPointField ImageField IntField ListField:可以将自定义的文档类型嵌套 MapField ObjectIdField ReferenceField LazyReferenceField SequenceField SortedListField StringField URLField UUIDField PointField LineStringField PolygonField MultiPointField MultiLineStringField MultiPolygonField
5.使用mongoengine创建数据库连接
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;
构建文档模型,插入数据
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') math_score = Score(name='math', value=94) chinese_score = Score(name='chinese', value=100) python_score = Score(name='python', value=99) for i in range(10): students = Students(name='robby{}'.format(i), age=int('{}'.format(i)), hobby='read', gender='M', score=[math_score, chinese_score, python_score]) students.save()
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)
修改、更新、删除数据
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') specific_document = Students.objects.filter(name='robby3') specific_document.update(set__age=100) specific_document.update_one(set__age=100) for document in specific_document: document.name = 'ROBBY100' document.save() for document in specific_document: document.delete()
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;
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;
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