Soft Deletes & Historical State in Graph Databases

1. Introduction

In the context of graph databases, managing data integrity and historical context is crucial. This lesson covers two important strategies: Soft Deletes and Historical State.

2. Soft Deletes

Soft deletes refer to the practice of marking data as deleted without actually removing it from the database. This allows for data recovery and auditing.

Implementation

To implement soft deletes in a graph database, you typically add a boolean property to the node representing whether it is deleted.

MATCH (n:User {id: 123}) 
SET n.isDeleted = true

3. Historical State

Tracking the historical state of data involves maintaining previous versions of nodes or relationships. This can provide context for changes over time.

Implementation

To track historical state, you can create a new node for each version of a data entity or use properties to store historical values.

MATCH (n:User {id: 123})
CREATE (n)-[:HAD_VERSION]->(v:UserVersion {name: n.name, email: n.email, updated: timestamp()})
SET n.name = 'New Name', n.email = 'newemail@example.com'

4. Workflow

The following flowchart outlines the typical workflow for managing soft deletes and historical state in a graph database.

graph TD;
    A[Start] --> B{Is Data Deleted?};
    B -- Yes --> C[Set isDeleted = true];
    B -- No --> D[Update Node];
    D --> E[Create Historical Version];
    C --> F[End];
    D --> F;

5. Best Practices

Here are some best practices to consider when implementing soft deletes and historical state:

• Always mark deleted nodes instead of removing them.
• Periodically archive or purge old versions to maintain performance.
• Implement proper indexing on soft delete flags for efficient queries.
• Document the business rules around data deletion and versioning.

6. FAQ