[Flutter Drift] Ensuring Unique Primary Keys in Drift: Auto vs Manual ID

Posted on Edited on In , , , Views: Word count in article: 1.6k Reading time ≈ 1 mins.

Ensuring Unique Primary Keys in Drift: Auto vs Manual ID

When working with the Drift ORM in Flutter, ensuring that your table’s primary key remains unique is essential for reliable data management. Depending on your data model, Drift offers two simple yet powerful approaches to enforce uniqueness:

✅ 1. Auto-Increment Integer ID (The Simple Way)

For most use cases, letting the database handle ID generation is the easiest and safest choice:

1
2
3
4
5
class WordMeanings extends Table {
  IntColumn get id => integer().autoIncrement()(); // Auto-increment primary key
  IntColumn get wordId => integer()();
  TextColumn get meaning => text()();
}

With autoIncrement(), Drift guarantees that each new record gets a unique integer ID automatically. You don’t have to worry about duplicates — Drift will manage this for you.

✅ 2. Custom ID Types (Manual Control)

If you prefer more control, such as using a string ID (e.g., UUIDs, hashes, etc.), you can manually define the primary key:

1
2
3
4
5
6
7
8
class WordMeanings extends Table {
  TextColumn get id => text()(); // Custom string ID
  IntColumn get wordId => integer()();
  TextColumn get meaning => text()();

  @override
  Set<Column> get primaryKey => {id}; // Explicitly define primary key
}

As long as you declare the primaryKey override, Drift will enforce uniqueness on the id field, regardless of its type.

🔑 When to Use Which?

Scenario Recommended Approach
Simple numeric IDs Auto-increment integers
Custom logic IDs (e.g., wordId+meaning hash) Manual primary key declaration

✅ Conclusion

Both auto-incremented integers and manually defined primary keys are fully supported in Drift. The choice depends on whether you want the database to handle ID uniqueness or if your business logic requires custom identifiers.

References