중단 없이 스키마 발전시키기

// Add a new required field 'phoneNumber' to the validator
db.runCommand({
  collMod: 'users',
  validator: {
    $jsonSchema: {
      bsonType: 'object',
      required: ['name', 'email', 'phoneNumber'],
      properties: {
        name:        { bsonType: 'string' },
        email:       { bsonType: 'string' },
        phoneNumber: { bsonType: 'string' }
      }
    }
  },
  validationLevel: 'moderate',
  validationAction: 'warn'
});

// Application code that handles both old and new document shapes
async function getUserPhone(userId) {
  const user = await db.collection('users').findOne({ _id: userId });
  // Provide a fallback for documents written before the migration
  return user.phoneNumber || 'Not provided';
}

// Backfill: set phoneNumber to '' for documents that lack it
const collection = db.collection('users');
const cursor = collection.find({ phoneNumber: { $exists: false } });

const batchSize = 500;
let batch = [];

for await (const doc of cursor) {
  batch.push({
    updateOne: {
      filter: { _id: doc._id },
      update: { $set: { phoneNumber: '' } }
    }
  });
  if (batch.length === batchSize) {
    await collection.bulkWrite(batch, { ordered: false });
    console.log('Processed', batchSize, 'docs');
    batch = [];
  }
}
if (batch.length) await collection.bulkWrite(batch, { ordered: false });
console.log('Backfill complete');

// Enable full enforcement after backfill is verified
db.runCommand({
  collMod: 'users',
  validationLevel: 'strict',
  validationAction: 'error'
});
console.log('Full schema enforcement enabled');

// Backfill: rename fullName to name for all existing documents
db.users.updateMany(
  { fullName: { $exists: true }, name: { $exists: false } },
  [{ $set: { name: '$fullName' } }, { $unset: 'fullName' }]
);

// Insert new document with schema version
db.products.insertOne({
  schemaVersion: 2,
  name: 'Widget Pro',
  priceUSD: 49.99,
  categories: ['electronics']
});

// Application transformer
function normalise(doc) {
  if (doc.schemaVersion === 1) {
    // v1 used 'price' instead of 'priceUSD'
    doc.priceUSD = doc.price;
    delete doc.price;
    doc.schemaVersion = 2;
  }
  return doc;
}

// Add optional 'avatarUrl' field to the validator
db.runCommand({
  collMod: 'users',
  validator: {
    $jsonSchema: {
      bsonType: 'object',
      required: ['name', 'email'],
      properties: {
        name:      { bsonType: 'string' },
        email:     { bsonType: 'string' },
        avatarUrl: { bsonType: 'string' }  // optional — no backfill needed
      }
    }
  }
});

// Remove the deprecated 'legacyCode' field from all documents
db.products.updateMany(
  { legacyCode: { $exists: true } },
  { $unset: { legacyCode: '' } }
);

// Verify no users are missing the new required field
const missing = await db.collection('users').countDocuments({
  phoneNumber: { $exists: false }
});
console.log('Documents missing phoneNumber:', missing);
// Should be 0 before enabling strict enforcement