pip install pymongo

from pymongo import MongoClient

# 創(chuàng)建一個(gè) MongoClient 對(duì)象，連接到本地的 MongoDB 服務(wù)器，默認(rèn)端口為 27017
client = MongoClient('mongodb://localhost:27017/')

# 選擇一個(gè)數(shù)據(jù)庫，如果該數(shù)據(jù)庫不存在，MongoDB 會(huì)在插入數(shù)據(jù)時(shí)自動(dòng)創(chuàng)建
db = client['test_database']

# 創(chuàng)建一個(gè)名為 test_collection 的集合
# 如果集合不存在，MongoDB 會(huì)在插入數(shù)據(jù)時(shí)自動(dòng)創(chuàng)建
collection = db['test_collection']

# 獲取數(shù)據(jù)庫中的所有集合名稱
collection_names = db.list_collection_names()
print("數(shù)據(jù)庫中的所有集合名稱:", collection_names)

# 刪除 test_collection 集合
db['test_collection'].drop()
print("test_collection 集合已刪除")

# 插入單個(gè)文檔
# 定義一個(gè)文檔，包含姓名、年齡和城市信息
document = {'name': 'Alice', 'age': 25, 'city': 'New York'}
# 使用 insert_one 方法插入單個(gè)文檔
result = collection.insert_one(document)
print(f"插入的單個(gè)文檔 ID: {result.inserted_id}")

# 插入多個(gè)文檔
# 定義一個(gè)包含多個(gè)文檔的列表
documents = [
    {'name': 'Bob', 'age': 30, 'city': 'Los Angeles'},
    {'name': 'Charlie', 'age': 35, 'city': 'Chicago'}
]
# 使用 insert_many 方法插入多個(gè)文檔
result = collection.insert_many(documents)
print(f"插入的多個(gè)文檔 ID: {result.inserted_ids}")

# 查詢單個(gè)文檔
# 定義查詢條件，查找姓名為 Alice 的文檔
query = {'name': 'Alice'}
# 使用 find_one 方法查詢單個(gè)文檔
result = collection.find_one(query)
print("查詢到的單個(gè)文檔:", result)

# 查詢多個(gè)文檔
# 定義查詢條件，查找年齡大于 28 的文檔
results = collection.find({'age': {'$gt': 28}})
print("查詢到的多個(gè)文檔:")
for result in results:
    print(result)

# 更新單個(gè)文檔
# 定義查詢條件，查找姓名為 Alice 的文檔
filter_query = {'name': 'Alice'}
# 定義更新操作，將年齡更新為 26
update_query = {'$set': {'age': 26}}
# 使用 update_one 方法更新單個(gè)文檔
result = collection.update_one(filter_query, update_query)
print(f"更新的單個(gè)文檔數(shù)量: {result.modified_count}")

# 更新多個(gè)文檔
# 定義查詢條件，查找城市為 New York 的文檔
filter_query = {'city': 'New York'}
# 定義更新操作，將年齡加 1
update_query = {'$inc': {'age': 1}}
# 使用 update_many 方法更新多個(gè)文檔
result = collection.update_many(filter_query, update_query)
print(f"更新的多個(gè)文檔數(shù)量: {result.modified_count}")

# 刪除單個(gè)文檔
# 定義查詢條件，查找姓名為 Alice 的文檔
filter_query = {'name': 'Alice'}
# 使用 delete_one 方法刪除單個(gè)文檔
result = collection.delete_one(filter_query)
print(f"刪除的單個(gè)文檔數(shù)量: {result.deleted_count}")

# 刪除多個(gè)文檔
# 定義查詢條件，查找年齡小于 30 的文檔
filter_query = {'age': {'$lt': 30}}
# 使用 delete_many 方法刪除多個(gè)文檔
result = collection.delete_many(filter_query)
print(f"刪除的多個(gè)文檔數(shù)量: {result.deleted_count}")

# 在 name 字段上創(chuàng)建升序索引
# 提高根據(jù)姓名查詢文檔的性能
collection.create_index([('name', 1)])
print("在 name 字段上創(chuàng)建了升序索引")

# 刪除 name 字段上的索引
collection.drop_index('name_1')
print("刪除了 name 字段上的索引")

from pymongo import MongoClient

# 連接到 MongoDB 服務(wù)器
client = MongoClient('mongodb://localhost:27017/')
# 選擇數(shù)據(jù)庫
db = client['test_database']
# 選擇集合
collection = db['test_collection']

pipeline = [
    {'$group': {'_id': '$city', 'count': {'$sum': 1}}}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$match': {'age': {'$gt': 25}}},
    {'$group': {'_id': '$city', 'count': {'$sum': 1}}}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$project': {'name': 1, 'double_age': {'$multiply': ['$age', 2]}, '_id': 0}}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$sort': {'age': -1}},
    {'$limit': 2}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$group': {'_id': None, 'average_age': {'$avg': '$age'}}}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$project': {'info': {'$concat': ['$name', ' lives in ', '$city']}, '_id': 0}}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

pipeline = [
    {'$group': {
        '_id': {
            'city': '$city',
            'age_group': {'$cond': [{'$gt': ['$age', 30]}, 'Over 30', 'Under 30']}
        },
        'count': {'$sum': 1}
    }}
]
results = collection.aggregate(pipeline)
for result in results:
    print(result)

# 假設(shè)已經(jīng)有 orders 和 products 集合
orders_collection = db['orders']
products_collection = db['products']

pipeline = [
    {
        '$lookup': {
            'from': 'products',
            'localField': 'product_id',
            'foreignField': '_id',
            'as': 'product_info'
        }
    }
]
results = orders_collection.aggregate(pipeline)
for result in results:
    print(result)