MongoDB Academy · Pelajaran

Tingkat dan Tindakan Validasi

Konfigurasikan validationLevel (strict vs moderate) dan validationAction (error vs warn) untuk mengatur cara pelanggaran ditangani.

Tingkat dan Tindakan Validasi adalah pelajaran MongoDB Academy gratis di CoddyKit. Ini adalah pelajaran 3 dari 4. Kamu bisa membaca pelajaran lengkapnya di bawah secara gratis — lalu praktikkan langsung di browser dengan editor kode bawaan dan tutor AI 24/7. Ini adalah bagian dari jalur belajar MongoDB Academy, dan progresmu tersinkronisasi di web dan aplikasi CoddyKit. Kursus MongoDB Academy mencakup 4 pelajaran total.

Bagian dari pelajaran ini belum diterjemahkan dan ditampilkan dalam bahasa Inggris.

Controlling How Strict Validation Is

MongoDB gives you two independent knobs to tune schema validation behaviour: validationLevel controls which documents are subject to validation, while validationAction controls what happens when a document fails validation. Together they let you introduce validation gradually into existing collections without breaking current data or applications.

validationLevel: strict

strict is the default validation level. In strict mode, every insert and every update must pass the validator—no exceptions. If an existing document in the collection already violates the schema, attempting to update it will still be checked against the validator. Strict mode gives you the strongest data quality guarantee but can be disruptive when applied to a collection with legacy non-conforming documents.

db.runCommand({
  collMod: 'users',
  validator: { $jsonSchema: { /* ... */ } },
  validationLevel: 'strict'   // default — all inserts and updates must pass
});

validationLevel: moderate

moderate level applies the validator only to new inserts and to updates of documents that already pass the validator. Existing non-conforming documents can still be updated without being forced to comply. This is a safe migration path: you enable the validator on a live collection without breaking updates to old documents that don't yet match the new schema.

db.runCommand({
  collMod: 'users',
  validator: { $jsonSchema: { /* ... */ } },
  validationLevel: 'moderate'  // existing non-conforming docs can still be updated
});

validationLevel: off

Setting validationLevel to off disables validation entirely, even if a validator is attached to the collection. This is useful during bulk data migrations or emergency hotfixes where you need to write non-conforming data temporarily. Always re-enable validation after the migration window closes.

// Temporarily disable validation for a migration window
db.runCommand({
  collMod: 'users',
  validationLevel: 'off'
});

// ... run migration ...

// Re-enable strict validation
db.runCommand({
  collMod: 'users',
  validationLevel: 'strict'
});

validationAction: error

error is the default validation action. When a document fails validation, MongoDB rejects the write entirely and returns an error to the client. The document is not written. This is the safest setting for production because it prevents malformed data from ever entering the collection.

db.runCommand({
  collMod: 'orders',
  validator: { $jsonSchema: { /* ... */ } },
  validationAction: 'error'   // default: reject the write, return an error
});

validationAction: warn

warn action allows the document to be written even if it fails validation, but logs a warning message to the MongoDB server log. This is useful during a transition period when you want to observe how many violations occur without blocking existing application traffic. After examining the logs and fixing the offenders, you can switch to error action.

db.runCommand({
  collMod: 'legacy_collection',
  validator: { $jsonSchema: { /* ... */ } },
  validationAction: 'warn'   // write succeeds, violation logged to server log
});

// The server log will show:
// [conn1] Document failed validation: { ... } with schema: { ... }

Combining Level and Action

The two settings compose independently. A common migration strategy is to start with validationLevel: 'moderate' and validationAction: 'warn'—new documents must comply but get logged on failure, while old documents are untouched. After observing the warnings and backfilling old data, switch to strict + error for full enforcement.

// Phase 1: observe without blocking
db.runCommand({
  collMod: 'users',
  validator: { $jsonSchema: { bsonType: 'object', required: ['email'] } },
  validationLevel: 'moderate',
  validationAction: 'warn'
});

// Phase 2 (after backfill): full enforcement
db.runCommand({
  collMod: 'users',
  validationLevel: 'strict',
  validationAction: 'error'
});

Reading the Validation Configuration

Check the current validation settings on a collection using db.getCollectionInfos(). The response includes options.validationLevel and options.validationAction alongside the full validator document. This is useful to audit all collections in a database and verify that production collections have strict enforcement enabled.

const info = db.getCollectionInfos({ name: 'users' });
const opts = info[0].options;
console.log('level:', opts.validationLevel);
console.log('action:', opts.validationAction);
console.log('validator:', JSON.stringify(opts.validator, null, 2));

Bypassing Validation With bypassDocumentValidation

Certain database operations support a bypassDocumentValidation: true option that skips the validator for that specific write. Only users with the bypassDocumentValidation privilege can use this option. It is intended for trusted admin scripts and data migrations only—never use it in application code as it defeats the purpose of having a validator.

// Insert a document bypassing validation — admin/migration use only
db.users.insertOne(
  { name: 'LegacyUser' },  // missing required email
  { bypassDocumentValidation: true }
);

Validation Warnings in the Server Log

When validationAction is warn, each failed validation is written to the MongoDB server log with the WRITE component and WARNING severity. The log line includes the database, collection, the violating document's _id, and the specific schema rule that was broken. You can monitor these logs with Atlas's log viewer or by tailing mongod.log on self-hosted deployments.

Practical Migration Playbook

Here is the recommended four-phase playbook for adding validation to an existing production collection:

Phase 1: Set moderate + warn — no impact, observe violations
Phase 2: Fix application code to send compliant documents
Phase 3: Backfill old non-conforming documents with a migration script
Phase 4: Switch to strict + error — full enforcement

Quick Check

Test your understanding of MongoDB & NoSQL Databases concepts from this lesson.

Lesson Recap

In this lesson you learned: validationLevel (strict/moderate/off) controls which documents are validated, validationAction (error/warn) controls whether failures block or just log, and combining moderate + warn is the safest way to introduce validation on a live collection. Next up we learn how to evolve schemas without downtime on a running MongoDB cluster.

Pertanyaan yang Sering Diajukan

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Apa yang akan aku pelajari di “Tingkat dan Tindakan Validasi”?

Konfigurasikan validationLevel (strict vs moderate) dan validationAction (error vs warn) untuk mengatur cara pelanggaran ditangani. Kamu berlatih MongoDB Academy dengan kode praktik yang langsung kamu jalankan di browser, dan tutor AI 24/7 menjawab pertanyaanmu saat kamu mengerjakan pelajaran ini.

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