本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。
$bsonSize
8.0.1 版的新功能。
Amazon DocumentDB 中的$bsonSize運算子會在編碼為 BSON 時傳回文件的位元組大小。
參數
範例 (MongoDB Shell)
下列範例示範如何使用 $bsonSize運算子傳回每個文件的 BSON 大小。
建立範例文件
db.items.insertMany([
{_id: 1, name: "a", tags: ["x"]},
{_id: 2, name: "ab", tags: ["x", "y", "z"]},
{_id: 3, name: "abc", tags: []}
]);
查詢範例
db.items.aggregate([
{ $project: { docSize: { $bsonSize: "$$ROOT" } } }
]);
輸出
[
{_id: 1, docSize: 46},
{_id: 2, docSize: 65},
{_id: 3, docSize: 39}
]
程式碼範例
若要檢視使用 $bsonSize 運算子的程式碼範例，請選擇您要使用的語言標籤：
- Node.js
-
const { MongoClient } = require('mongodb');
async function example() {
const client = new MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
try {
await client.connect();
const db = client.db('test');
const collection = db.collection('items');
const result = await collection.aggregate([
{ $project: { docSize: { $bsonSize: "$$ROOT" } } }
]).toArray();
console.log(result);
} finally {
await client.close();
}
}
example();
- Python
-
from pymongo import MongoClient
def example():
client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
try:
db = client['test']
collection = db['items']
result = list(collection.aggregate([
{'$project': {'docSize': {'$bsonSize': '$$ROOT'}}}
]))
print(result)
finally:
client.close()
example()
