实现“mongodb 查询不返回id”

简介

在使用MongoDB进行数据查询时，默认情况下返回的结果会包含文档的_id字段，该字段是MongoDB自动生成的唯一标识符。但有时我们希望查询结果不包含_id字段，本文将介绍如何实现这一需求。

流程图

graph LR
A[开始] --> B[创建数据库]
B --> C[创建集合并插入数据]
C --> D[执行查询操作]
D --> E[处理查询结果并输出]
E --> F[结束]

步骤说明

  1. 创建数据库：首先需要连接MongoDB数据库，并创建一个新的数据库。可以使用以下代码：
import pymongo

# 连接MongoDB数据库
client = pymongo.MongoClient("mongodb://localhost:27017/")

# 创建数据库
mydb = client["mydatabase"]
  1. 创建集合并插入数据：在创建数据库后，我们需要创建一个集合并插入一些数据用于查询操作。可以使用以下代码：
# 创建集合
mycol = mydb["customers"]

# 插入数据
data = [
  {"name": "John", "address": "Highway 37"},
  {"name": "Peter", "address": "Lowstreet 27"},
  {"name": "Amy", "address": "Apple st 652"},
  {"name": "Hannah", "address": "Mountain 21"},
  {"name": "Michael", "address": "Valley 345"},
  {"name": "Sandy", "address": "Ocean blvd 2"},
  {"name": "Betty", "address": "Green Grass 1"},
  {"name": "Richard", "address": "Sky st 331"},
  {"name": "Susan", "address": "One way 98"},
  {"name": "Vicky", "address": "Yellow Garden 2"},
  {"name": "Ben", "address": "Park Lane 38"},
  {"name": "William", "address": "Central st 954"},
  {"name": "Chuck", "address": "Main Road 989"},
  {"name": "Viola", "address": "Sideway 1633"}
]

mycol.insert_many(data)
  1. 执行查询操作：接下来，我们可以执行查询操作来获取数据库中的数据。可以使用以下代码：
# 查询数据，并设置_id字段为0表示不返回该字段
result = mycol.find({}, {"_id": 0})

# 打印查询结果
for doc in result:
    print(doc)
  1. 处理查询结果并输出：最后，我们需要处理查询结果并将其输出。可以使用以下代码：
# 打印查询结果
for doc in result:
    print(doc)

完整代码示例

import pymongo

# 连接MongoDB数据库
client = pymongo.MongoClient("mongodb://localhost:27017/")

# 创建数据库
mydb = client["mydatabase"]

# 创建集合
mycol = mydb["customers"]

# 插入数据
data = [
  {"name": "John", "address": "Highway 37"},
  {"name": "Peter", "address": "Lowstreet 27"},
  {"name": "Amy", "address": "Apple st 652"},
  {"name": "Hannah", "address": "Mountain 21"},
  {"name": "Michael", "address": "Valley 345"},
  {"name": "Sandy", "address": "Ocean blvd 2"},
  {"name": "Betty", "address": "Green Grass 1"},
  {"name": "Richard", "address": "Sky st 331"},
  {"name": "Susan", "address": "One way 98"},
  {"name": "Vicky", "address": "Yellow Garden 2"},
  {"name": "Ben", "address": "Park Lane 38"},
  {"name": "William", "address": "Central st 954"},
  {"name": "Chuck", "address": "Main Road 989"},
  {"name": "Viola", "address": "Sideway 1633"}
]

mycol.insert_many(data)

# 查询数据，并设置_id字段为0表示不返回该字段
result = mycol.find({}, {"_id": 0})

# 打印查询结果
for doc in result:
    print(doc)

序列图

sequenceDiagram
    participant 开发者
    participant 小白
    开发者->>小白: 提供实现思路和代码示例
    小白->>开发者: 确认理解并提问
    开发者->>小白: 解答疑惑并进一步