Special Tables

Appendix A — Configuration Reference

Special tables are fixed-purpose pseudo-tables that exist to document mapping decisions that don't correspond to a real source or target column. They appear in the project panels alongside regular tables and accept mappings like any other table, but their presence in a mapping carries specific meaning that Bridger uses when generating validation SQL and computing statistics.

The five special table types are fixed — they cannot be added or removed. What you can configure is the name used for each type in the project, so the table names match the conventions of your engagement.

The Five Types

Source Excluded — Map target columns here to document that they will not be populated during conversion. Use for fields handled by application logic, interfaces, manual entry, or future phases. Validation generates a null/default check confirming the column is not being loaded.

Target Excluded — Map source columns here to document that they will not be converted. Use for deprecated fields, duplicates, or source data with no target equivalent. These mappings are skipped entirely during validation script generation.

Database Default — Map target columns here when they should use the database schema's built-in DEFAULT constraint. No conversion logic is needed; the database handles it. Validation generates a null/default check confirming the column is not explicitly populated by the loader.

Conversion Default — Map target columns here when they should be populated with a specific hardcoded value during conversion. The Default Value field is shown and required for these mappings. Validation generates a query comparing actual loaded values against the expected default.

Stored Value — Map target columns here when they use a value previously computed or looked up during conversion — for example, a converted primary key reused across child tables. Validation generates a manual review stub, since the value source is dynamic and cannot be automatically verified.

Configuration Fields

Table Name — The name this special table type uses in the project. Defaults are provided (EXCLUDED, DATABASE_DEFAULT, CONVERSION_DEFAULT, STORED_VALUE) but can be changed to match engagement conventions. Renaming cascades automatically to all existing references throughout the workbook — mappings, column references, and library links are all updated.

Column Name — The name of the default column within the special table. Renaming this also cascades to existing references.

Description — Documents the intended use of this special table type within the workbook. Shown in the properties panel when the table is selected.