Implementing data versioning in Java MongoDB

16 Oct 2023

In data-driven applications, it is often crucial to keep track of changes made to data over time. Data versioning allows us to maintain historical records and view the evolution of our data. In this blog post, we will explore how to implement data versioning in a Java MongoDB application.

Introduction
Setting up MongoDB
Implementing Data Versioning
Conclusion

Introduction

MongoDB is a popular NoSQL database that provides powerful features for document storage. To implement data versioning in a MongoDB application, we need to introduce a mechanism for tracking changes to the data.

Setting up MongoDB

Before we dive into implementing data versioning, let’s set up MongoDB in our Java application. We’ll need to include the MongoDB Java driver as a dependency in our project.

// Maven dependency
<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongodb-driver-sync</artifactId>
    <version>4.2.3</version>
</dependency>

Next, we can connect to our MongoDB instance using the following code:

// MongoDB connection setup
String connectionString = "mongodb://localhost:27017";
MongoClientSettings settings = MongoClientSettings.builder()
        .applyConnectionString(new ConnectionString(connectionString))
        .build();
MongoClient mongoClient = MongoClients.create(settings);
MongoDatabase database = mongoClient.getDatabase("mydb");

Implementing Data Versioning

Modeling Data Version

To enable data versioning, we need to modify our data model by introducing a version field. This field will store the version number for each document.

public class DataVersion {
    private int version;

    public int getVersion() {
        return version;
    }

    public void setVersion(int version) {
        this.version = version;
    }
}

public class MyData {
    private String id;
    private String name;
    private DataVersion dataVersion;

    // Getters and setters
}

Creating a Data Versioning Service

Next, let’s create a service that will handle the data versioning logic. We’ll define methods for creating new versions and retrieving a specific version of a document.

public class DataVersioningService {
    private MongoCollection<Document> collection;

    public DataVersioningService(MongoCollection<Document> collection) {
        this.collection = collection;
    }

    public void createNewVersion(String id, MyData newData) {
        MyData currentData = retrieveLatestVersion(id);
        int latestVersion = currentData.getDataVersion().getVersion();
        newData.getDataVersion().setVersion(latestVersion + 1);
        collection.insertOne(Document.parse(new Gson().toJson(newData)));
    }

    public MyData retrieveVersion(String id, int version) {
        return collection.find(and(eq("_id", id), eq("dataVersion.version", version)))
                .first()
                .map(document -> new Gson().fromJson(document.toJson(), MyData.class))
                .orElse(null);
    }

    // Other methods...
}

Updating Documents with Versioning

To update a document with versioning, we’ll need to use the DataVersioningService class. Here’s an example of how to update an existing document:

DataVersioningService versioningService = new DataVersioningService(database.getCollection("mycollection"));
MyData existingData = versioningService.retrieveLatestVersion("my_id");
existingData.setName("Updated Name");
versioningService.createNewVersion("my_id", existingData);

By creating a new version of the document, we ensure that the previous version is preserved in our data versioning system.

Conclusion

In this blog post, we explored how to implement data versioning in a Java MongoDB application. By introducing a version field in our data model and using a data versioning service, we can easily track and retrieve historical versions of our data.

Table of Contents