This pull request introduces significant improvements to the handling of the Replace and Save operations for multiple database drivers, especially for MSSQL and PostgreSQL. The changes ensure that these operations now auto-detect primary keys when conflict columns are not explicitly provided, improving usability and aligning behavior across drivers. Additionally, the pull request updates related tests to reflect these enhancements and includes some minor documentation and code cleanup.

Key changes:

Enhanced Replace/Save Logic for Database Drivers

• MSSQL Driver:

  • Replace and Save operations now auto-detect primary keys if OnConflict is not specified, using the MERGE statement for upsert functionality. If no primary key is found in the data, a detailed error is returned. [1] [2]
  • Updated tests to verify that Replace correctly updates or inserts records, and that missing conflict columns are properly handled. [1] [2]

• PostgreSQL Driver:

  • Similar to MSSQL, Replace and Save now auto-detect primary keys for conflict resolution if OnConflict is not set, and treat Replace as a Save operation.
  • Adjusted tests to ensure Save and Replace work as expected, including verifying data replacement and insertion. [1] [2] [3]

• DM Driver:

  • Improved conflict detection: now checks that at least one primary key exists in the provided data when OnConflict is not specified, and provides clearer error messages.
  • Refactored to use the core method for primary key detection and removed redundant code.

Minor Improvements and Documentation

• Added clarifying comments to DoInsert methods for ClickHouse, DM, MSSQL, Oracle, and PostgreSQL drivers, specifying that the input list must have at least one validated record. [1] [2] [3] [4] [5]
• Minor code and comment cleanups, including improved formatting and error handling. [1] [2] [3] [4] [5]

Workflow and Documentation Updates

• Updated example Docker commands in the CI workflow for consistency and clarity. [1] [2] [3] [4] [5] [6]
• Removed outdated note about Replace support from the SQLite driver documentation.

These changes improve the consistency, reliability, and developer experience when performing upsert operations across different database backends.