MongoDB的基于位置的分片和区域 vs Couchbase的基于ID的分片

MongoDB的基于位置的分片和区域解决方案示例代码：

1. 安装MongoDB和相关驱动

npm install mongodb

2. 连接MongoDB集群

const { MongoClient } = require('mongodb');

const uri = "mongodb://mongos1.example.com:27017,mongos2.example.com:27017,mongos3.example.com:27017";
const client = new MongoClient(uri);

async function connect() {
  try {
    await client.connect();
    console.log("Connected to MongoDB cluster");
  } catch (err) {
    console.error("Error connecting to MongoDB cluster", err);
  }
}

connect();

3. 创建分片集合和索引

async function createShardedCollection(dbName, collectionName, shardKey) {
  const db = client.db(dbName);
  const collection = db.collection(collectionName);
  
  // 创建分片集合
  await db.command({ shardCollection: `${dbName}.${collectionName}`, key: shardKey });

  // 创建索引
  await collection.createIndex({ location: "2dsphere" });

  console.log(`Sharded collection ${dbName}.${collectionName} created with shard key ${shardKey}`);
}

createShardedCollection("mydatabase", "mycollection", { location: "2dsphere" });

Couchbase的基于ID的分片解决方案示例代码：

1. 安装Couchbase和相关驱动

npm install couchbase

2. 连接Couchbase集群

const { Cluster, Authenticator } = require('couchbase');

const cluster = new Cluster('couchbase://couchbase1.example.com,couchbase2.example.com,couchbase3.example.com');
const authenticator = new Authenticator();
authenticator.username = 'username';
authenticator.password = 'password';
cluster.authenticate(authenticator);

const bucket = cluster.bucket('mybucket');
const collection = bucket.defaultCollection();

console.log("Connected to Couchbase cluster");

3. 创建分片集合和索引

async function createShardedCollection(collectionName) {
  // 创建集合
  await collection.createCollection(collectionName);

  // 创建分片索引
  await collection.createIndex(collectionName, { fields: ["id"], numPartitions: 4 });

  console.log(`Sharded collection ${collectionName} created with ID-based sharding`);
}

createShardedCollection("mycollection");

以上示例代码演示了如何连接MongoDB和Couchbase集群，并创建基于位置的分片和区域以及基于ID的分片。请根据自己的环境和需求进行适当的修改。