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What are Delta Tables?

Delta Tables are a modern data storage format that combine the scalability of data lakes with the reliability of data warehouses. They offer powerful features like version control, schema enforcement, time travel, and ACID transactions, making them ideal for everything from analytics to machine learning. In Nekt, Delta Tables are automatically applied to data in the Raw Layer, giving your data a structured and scalable foundation from the moment it enters the platform.

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Why Use Delta Tables?

Delta Tables address many of the challenges of traditional data storage formats by offering:
  • Version Control
    Track changes and access historical versions of your data at any time.
  • Schema Enforcement
    Protect data integrity with structure-aware write operations.
  • Data Lineage
    Automatically log every change for full transparency and governance.
  • Efficient Querying
    Optimize performance for large-scale analytics and ML workloads.
  • ACID Transactions
    Ensure data consistency, even in concurrent and complex workflows.

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How Delta Tables Work in Nekt

In Nekt, Delta Tables are applied automatically in the Raw Layer, so you can take advantage of structured storage and reliable querying right away. From there, the architecture flows naturally:
  1. Data is stored in Delta format
    Insertions, updates, and deletions are fully logged and versioned.
  2. Users manage transformations in Trusted and Service Layers
    Clean, standardize, and prepare your data based on trusted Delta-backed sources.
  3. Time Travel empowers recovery and analysis
    Go back to a previous version of your table whenever needed.
This design ensures that every stage of your pipeline is reliable, traceable, and scalable.

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Key Features of Delta Tables

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Version Control

Each write operation creates a new version of your table. This makes it easy to:
  • Reproduce past analyses
  • Audit changes
  • Debug issues in your pipeline

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Schema Evolution

Delta Tables can detect and adapt to changes in your data schema, so your workflows remain flexible without sacrificing integrity.

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Efficient Storage

Delta Tables use compression and intelligent caching to reduce storage costs while improving performance.

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Time Travel

Delta Tables in Nekt support time travel, allowing you to query previous versions of your data. This is particularly useful for debugging, audits, or restoring deleted records. Default retention settings:
  • Delta Log Retention Duration: 30 days
    You can navigate past table versions for up to 30 days.
  • Delta Deleted File Retention Duration: 7 days
    Deleted files are retained for an additional 7 days after the log expires.
    (Access to these files requires a manual request.)
Both settings can be customized in the Settings tab of each table.

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Example:

If your table is updated daily:
  • You can go back up to 30 days using time travel.
  • After 30 days, the physical files are retained for 7 more days.
  • After 37 days, the data becomes unrecoverable unless otherwise configured.

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Delta Tables + AI/ML

Delta Tables provide the performance, consistency, and history needed for training and deploying machine learning models. You can trust that your input data is:
  • Clean and versioned
  • Easily reproducible
  • Governed with full audit trails
Whether you’re building dashboards or training models, Delta Tables support high-quality, production-grade workflows.

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Explore Delta Tables in Nekt

Delta Tables are the backbone of structured data management in Nekt. By combining speed, reliability, and flexibility, they help you manage your data with confidence—whether you’re exploring trends, training ML models, or simply keeping your pipelines clean.
Ready to dive deeper? Open a table in the Catalog, visit the Settings tab, and start exploring your Delta-backed data today.