Databricks Certified Data Engineer - Associate

Explanation

Delta tables use a storage organization where data is stored in Parquet files, and metadata is stored in JSON files in the _delta_log directory. This creates a collection of files that work together to provide ACID transactions, time travel, and other Delta Lake features.

Key points about Delta table storage:

1. Data files: Stored as Parquet files containing the actual table data
2. Transaction log: Stored as JSON files in the _delta_log directory, containing:
   • Metadata about the table schema
   • Transaction history
   • File statistics
   • Version information
3. Checkpoint files: Periodic snapshots of the transaction log for faster access

Why other options are incorrect:

• A: Incorrect - Delta tables are not stored in a single file; they use multiple files
• B: Incorrect - Data is not stored in a single file; it's distributed across multiple Parquet files
• D: Incorrect - The collection of files includes more than just data; it includes metadata and transaction logs
• E: Incorrect - Delta tables are not single files and contain more than just data

This distributed file organization enables Delta Lake's key features like ACID transactions, scalable metadata handling, and efficient time travel capabilities.