ML Design Pattern——Bridged Schema

The bridged schema design pattern is a machine learning (ML) technique that allows two schema to share a common vocabulary and format while ensuring data compatibility. This pattern is particularly useful when there is a need to integrate data from different data sources or formats.

How does the Bridged Schema pattern work

The bridged schema pattern works by mapping the fields and schemas from two datasets into a common format. This mapping process ensures that data from both sources can be seamlessly combined and analyzed.

One of the key advantages of using the bridged schema pattern is that it simplifies the integration process between different datasets. By mapping the fields and schemas, it becomes easier to manage and analyze the data. This is particularly important in situations where the data sources are in different formats or structures.

Another advantage of the Bridged Schema pattern is that it provides flexibility in the schema design. It allows for variations in the schema while maintaining data compatibility. This flexibility ensures that the system can accommodate changes in data formats or schemas without requiring a complete overhaul of the data processing pipelines.

When to use the Bridged Schema pattern

The Bridged Schema pattern is commonly used in situations where there is a need to integrate data from multiple data sources. For example, in enterprise applications, it is common to have data stored in different databases or systems. In such cases, the bridged schema pattern can be used to merge the data into a single schema for analysis and visualization.

Additionally, this pattern can be used in situations where there is a need to transform or migrate data from one format to another. By mapping the schemas, it becomes easier to process the data in the new format while maintaining data compatibility.

Example of the Bridged Schema pattern

Let's take an example to better understand how the bridged schema pattern works. Consider a business scenario where a company needs to integrate the data from two different databases. One database contains customer records, while the other database contains information on products.

In order to combine and analyze the data, the company needs to create a bridged schema that maps the fields and schemas of the two databases. This bridged schema would contain the common fields and attributes from both datasets.

By implementing the bridged schema pattern, the company can seamlessly combine the customer data with the product data. This would enable analysts to perform queries and derive insights by combining the data from different databases.

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Purpose:

• To effectively handle datasets where feature availability or schema evolves over time, ensuring model compatibility and consistency.
• To seamlessly integrate new features or data sources without compromising model performance or retraining from scratch.

Key Scenarios:

• Gradual feature additions: New features become available after model training.
• Data schema changes: Existing feature definitions or formats undergo modifications.
• Data source integrations: Data from multiple sources with varying schemas need to be combined for model training.

Implementation:

1. Feature Mapping:

   • Define a mapping table or function to translate between original and new features.
   • Handle missing values for new features in older data appropriately (e.g., with placeholders or imputation).

2. Schema Versioning:

   • Keep track of schema versions associated with different datasets or model training iterations.
   • Implement logic to apply appropriate mappings based on schema versions.

3. Feature Engineering:

   • Re-engineer features for compatibility across versions, potentially using aggregations or transformations.
   • Consider feature normalization or standardization for consistency.

Example:

• Initial model: Trained on data with features A, B, and C.
• New data: Includes features A, B, C, and D.
• Bridged schema: Maps feature D to a placeholder value (e.g., NaN) in older data for model compatibility.

Benefits:

• Continuous improvement: Facilitates ongoing model updates and refinements without complete retraining.
• Data flexibility: Accommodates evolving data landscapes and heterogeneous sources.
• Reproducibility: Ensures consistent model behavior across different data versions.

Considerations:

• Mapping complexity: Accurate mapping and feature engineering can be challenging, especially with intricate schema changes.
• Performance overhead: Feature mapping and versioning logic might introduce computational overhead.
• Testing and validation: Thorough testing is crucial to guarantee model accuracy and robustness across different schema versions.

Additional Notes:

• Often combined with other design patterns like Feature Store and Workflow Pipeline for robust ML systems.
• Carefully consider the trade-offs between flexibility and potential complexity when adopting this pattern.