52.Python操作MongoDB文档数据库

（五十二）Python操作MongoDB文档数据库

1：Pymongo 详解

安装

pip install pymongo

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

2：MongoDB ODM 详解

MongoEngine官方文档

MongoDB ODM 与 Django ORM使用方法类似

安装

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

创建连接

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

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()

1.Pymongo 详解

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；
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；

2.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；

3.使用mongoengine创建数据库连接的参数讲解

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；

4.mongoengine查询的方法

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；

5.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；

posted @ 2024-12-13 16:45 钟桂耀阅读(22) 评论(0) 编辑收藏举报

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