MongoDB Atlas에서 데이터 쓰기 - 함수

exports = function() {
  const mongodb = context.services.get("mongodb-atlas");
  const itemsCollection = mongodb.db("store").collection("items");
  const purchasesCollection = mongodb.db("store").collection("purchases");
  // ... paste snippet here ...
}

db.products.update(
  { sku: "unknown" },
  { $unset: { _id__baas_transaction: "" } }
)

exports = async function(arg){
    const doc1 = { "name": "velvet elvis", "quantity": 20, "reviews": [] };
    const doc2 = { "name": "mock turtleneck",  "quantity": 30, "reviews": [] };
    var collection = context.services.get("mongodb-atlas")
        .db("store")
        .collection("purchases");
    return await collection.bulkWrite(
        [{ insertOne: doc1}, { insertOne: doc2}],
        {ordered:true});
};

exports = function () {
    const client = context.services.get("mongodb-atlas");
  
    db = client.db("exampleDatabase");
  
    accounts = db.collection("accounts");
    browniePointsTrades = db.collection("browniePointsTrades");
  
    // create user accounts with initial balances
    accounts.insertOne({ name: "henry", browniePoints: 42 });
    accounts.insertOne({ name: "michelle", browniePoints: 144 });
  
    // trade points between user accounts in a transaction
    tradeBrowniePoints(
      client,
      accounts,
      browniePointsTrades,
      "michelle",
      "henry",
      5
    );
  
    return "Successfully traded brownie points.";
  };
  
  async function tradeBrowniePoints(
    client,
    accounts,
    browniePointsTrades,
    userAddPoints,
    userSubtractPoints,
    pointVolume
  ) {
    // Step 1: Start a Client Session
    const session = client.startSession();
  
    // Step 2: Optional. Define options to use for the transaction
    const transactionOptions = {
      readPreference: "primary",
      readConcern: { level: "local" },
      writeConcern: { w: "majority" },
    };
  
    // Step 3: Use withTransaction to start a transaction, execute the callback, and commit (or abort on error)
    // Note: The callback for withTransaction MUST be async and/or return a Promise.
    try {
      await session.withTransaction(async () => {
        // Step 4: Execute the queries you would like to include in one atomic transaction
        // Important:: You must pass the session to the operations
        await accounts.updateOne(
          { name: userSubtractPoints },
          { $inc: { browniePoints: -1 * pointVolume } },
          { session }
        );
        await accounts.updateOne(
          { name: userAddPoints },
          { $inc: { browniePoints: pointVolume } },
          { session }
        );
        await browniePointsTrades.insertOne(
          {
            userAddPoints: userAddPoints,
            userSubtractPoints: userSubtractPoints,
            pointVolume: pointVolume,
          },
          { session }
        );
      }, transactionOptions);
    } catch (err) {
      // Step 5: Handle errors with a transaction abort
      await session.abortTransaction();
    } finally {
      // Step 6: End the session when you complete the transaction
      await session.endSession();
    }
  }