Python操作MongoDB文檔數據庫

1.Pymongo 安裝

安裝pymongo：

pip install pymongo

• PyMongo是驅動程序，使python程序能夠使用Mongodb數據庫，使用python編寫而成；

2.Pymongo 方法

• insert_one()：插入一條記錄；
• insert()：插入多條記錄；
• find_one()：查詢一條記錄，不帶任何參數返回第一條記錄，帶參數則按條件查找返回；
• find()：查詢多條記錄，不帶參數返回所有記錄，帶參數按條件查找返回；
• count()：查看記錄總數；
• create_index()：創建索引；
• update_one()：更新匹配到的第一條數據；
• update()：更新匹配到的所有數據；
• remove()：刪除記錄，不帶參表示刪除全部記錄，帶參則表示按條件刪除；
• delete_one()：刪除單條記錄；
• delete_many()：刪除多條記錄；

3.Pymongo 中的操作

• 查看數據庫

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())

• 獲取數據庫實例

test_db = connect['test']

• 獲取collection實例

collection = test_db['students']

• 插入一行document, 查詢一行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",) # 獲取db test_db = connect['test'] # 獲取collection collection = test_db['students'] # 構建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) # 通過條件過濾出一條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：如果需要通過id查詢一行document，需要將id包裝為ObjectId類的實例對象 from bson.objectid import ObjectId collection.find_one({'_id': ObjectId('5c2b18dedea5818bbd73b94c')})

• 插入多行documents, 查詢多行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",) # 獲取db test_db = connect['test'] # 獲取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) # 通過條件過濾出多條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)

• 范圍比較查詢

from pymongo import MongoClient from datetime import datetime connect = MongoClient(host='localhost', port=27017, username="root", password="123456",) # 獲取db test_db = connect['test'] # 獲取collection collection = test_db['students'] # 通過條件過濾時間小於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)

• 創建索引

from pymongo import MongoClient import pymongo from datetime import datetime connect = MongoClient(host='localhost', port=27017, username="root", password="123456",) # 獲取db test_db = connect['test'] # 獲取collection collection = test_db['students'] # 創建字段索引 collection.create_index(keys=[("name", pymongo.DESCENDING)], unique=True) # 查詢索引 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",) # 獲取db test_db = connect['test'] # 獲取collection collection = test_db['students'] result = collection.update({'name': 'robby'}, {'$set': {"name": "Petter"}}) print(result) 注意：還有update_many()方法

• document刪除

from pymongo import MongoClient
connect = MongoClient(host='localhost', port=27017, username="root", password="123456",) # 獲取db test_db = connect['test'] # 獲取collection collection = test_db['students'] result = collection.delete_one({'name': 'Petter'}) print(result.deleted_count) 注意：還有delete_many()方法

4.MongoDB ODM 詳解

• MongoDB ODM 與 Django ORM使用方法類似；
• MongoEngine是一個對象文檔映射器，用Python編寫，用於處理MongoDB；
• MongoEngine提供的抽象是基於類的，創建的所有模型都是類；

# 安裝mongoengine pip install mongoengine

• mongoengine使用的字段類型

BinaryField
BooleanField
ComplexDateTimeField
DateTimeField
DecimalField
DictField
DynamicField
EmailField
EmbeddedDocumentField
EmbeddedDocumentListField
FileField
FloatField
GenericEmbeddedDocumentField
GenericReferenceField
GenericLazyReferenceField
GeoPointField
ImageField
IntField
ListField:可以將自定義的文檔類型嵌套 MapField ObjectIdField ReferenceField LazyReferenceField SequenceField SortedListField StringField URLField UUIDField PointField LineStringField PolygonField MultiPointField MultiLineStringField MultiPolygonField

5.使用mongoengine創建數據庫連接

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：要使用的數據庫的名稱，以便與connect兼容；
• host ：要連接的mongod實例的主機名；
• port ：運行mongod實例的端口；
• username：用於進行身份驗證的用戶名；
• password：用於進行身份驗證的密碼；
• authentication_source ：要進行身份驗證的數據庫；

構建文檔模型，插入數據

from mongoengine import connect, \ Document, \ StringField,\ IntField, \ FloatField,\ ListField, \ EmbeddedDocumentField,\ DateTimeField, \ EmbeddedDocument from datetime import datetime # 嵌套文檔 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) # 這里使用到了嵌套文檔，這個列表中的每一個元素都是一個字典，因此使用嵌套類型的字段 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()

查詢數據

from mongoengine import connect, \ Document, \ StringField,\ IntField, \ FloatField,\ ListField, \ EmbeddedDocumentField,\ DateTimeField, \ EmbeddedDocument from datetime import datetime # 嵌套文檔 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) # 這里使用到了嵌套文檔，這個列表中的每一個元素都是一個字典，因此使用嵌套類型的字段 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() # 如果只有一條，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、刪除數據

from mongoengine import connect, \ Document, \ StringField,\ IntField, \ FloatField,\ ListField, \ EmbeddedDocumentField,\ DateTimeField, \ EmbeddedDocument from datetime import datetime # 嵌套文檔 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) # 這里使用到了嵌套文檔，這個列表中的每一個元素都是一個字典，因此使用嵌套類型的字段 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()：返回所有文檔；
• all_fields()：包括所有字段；
• as_pymongo()：返回的不是Document實例 而是pymongo值；
• average()：平均值超過指定字段的值；
• batch_size()：限制單個批次中返回的文檔數量；
• clone()：創建當前查詢集的副本；
• comment()：在查詢中添加注釋；
• count()：計算查詢中的選定元素；
• create()：創建新對象，返回保存的對象實例；
• delete()：刪除查詢匹配的文檔；
• distinct()：返回給定字段的不同值列表；

嵌入式文檔查詢的方法

• count()：列表中嵌入文檔的數量，列表的長度；
• create()：創建新的嵌入式文檔並將其保存到數據庫中；
• delete()：從數據庫中刪除嵌入的文檔；
• exclude(** kwargs )：通過使用給定的關鍵字參數排除嵌入的文檔來過濾列表；
• first()：返回列表中的第一個嵌入文檔；
• get()：檢索由給定關鍵字參數確定的嵌入文檔；
• save()：保存祖先文檔；
• update()：使用給定的替換值更新嵌入的文檔；