Database Migration with Mongock and Spring Boot

Question

I have a class

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document("animal")
public class Animal {
    private String id;
    private boolean isBirthYear;
}

I want to update class to:

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document("animal")
public class Animal {
    private String id;
    private long isBirthYear;
}

Don't care about code convention. I want to write a migration to convert data from boolean to long in mongodb.

I try to create a new class

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document("animal")
public class AnimalV2 {
    private String id;
    private long isBirthYear;
}

but I think that is not a good solution.

Answer 1

As I think that you are looking for a a way to manage this migration with Mongock, I recommend to perform the actual MongoDB migration that @wpdnqd is providing inside a ChangeUnit.

Something like this

@ChangeUnit(id = "udpate-animal-birthday", order = "1")
class ACreateCollection {

    @Execution
    fun execution(mongoClient: MongoClient) {
           var database = mongoClient.getDatabase("your-database-name");
            var collection = database.getCollection("animal");

            // Get all documents in the collection
            try (var cursor = collection.find().iterator()) {
                while (cursor.hasNext()) {
                    var document = cursor.next();

                    // Convert boolean to long for the isBirthYear field
                    if (document.containsKey("isBirthYear")) {
                        var isBirthYear = document.getBoolean("isBirthYear");
                        document.put("isBirthYear", isBirthYear ? 1L : 0L);
                    }

                    // Save the updated document back to the collection
                    collection.replaceOne(new Document("_id", document.getObjectId("_id")), document);
                }
            }
       
    }
}

For more example, take a look to this repo and the official documentation

Answer 2

import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import org.bson.Document;

public class AnimalMigration {

    public static void main(String[] args) {
        try (var mongoClient = MongoClients.create("your-mongodb-connection-string")) {
            var database = mongoClient.getDatabase("your-database-name");
            var collection = database.getCollection("animal");

            // Get all documents in the collection
            try (var cursor = collection.find().iterator()) {
                while (cursor.hasNext()) {
                    var document = cursor.next();

                    // Convert boolean to long for the isBirthYear field
                    if (document.containsKey("isBirthYear")) {
                        var isBirthYear = document.getBoolean("isBirthYear");
                        document.put("isBirthYear", isBirthYear ? 1L : 0L);
                    }

                    // Save the updated document back to the collection
                    collection.replaceOne(new Document("_id", document.getObjectId("_id")), document);
                }
            }
        }
    }
}