metabuilder/txt/sql_adapter_split_20260207-195134.md

SQL Adapter Header Split - 2026-02-07

Objective

Reduce sql_adapter_base.hpp from 157 lines to under 150 LOC while maintaining clear interface.

Solution

Extracted helper declarations and type definitions to separate headers using a three-file split:

File Structure

1. sql_types.hpp (49 lines)

   • SqlParam - Parameter binding structure
   • SqlRow - Result row structure
   • SqlError - Error codes and message
   • Note: Dialect enum remains in sql_connection.hpp (already existed)

2. sql_adapter_helpers.hpp (52 lines)

   • SqlQueryBuilder - SQL query construction (INSERT, SELECT, UPDATE, DELETE)
   • SqlDataConverter - JSON ↔ SQL row conversion
   • SqlUtils - String utilities (snake_case, placeholders, joins)

3. sql_adapter_base.hpp (94 lines) ✅

   • Main SqlAdapter class interface
   • Generic CRUD operations (11 methods)
   • Bulk operations (3 methods)
   • Query operations (3 methods)
   • Metadata operations (2 methods)
   • Protected methods (schema loading, query execution)

Changes Made

Extracted to sql_types.hpp

• Moved SqlParam, SqlRow, SqlError structs
• Removed duplicate Dialect enum (already in sql_connection.hpp)

Extracted to sql_adapter_helpers.hpp

• Created static helper classes for SQL building, data conversion, utilities
• Added sql_connection.hpp include for Dialect enum

Simplified sql_adapter_base.hpp

• Reduced includes from 14 to 7
• Removed inline implementations from protected methods
• Condensed ConnectionGuard destructor to single line
• Added helper includes: sql_types.hpp, sql_adapter_helpers.hpp

Results

Metric	Before	After	Change
sql_adapter_base.hpp LOC	157	94	-63 (-40%)
Target met	❌	✅	Under 150 LOC
Files created	1	3	+2 helpers
Total LOC	157	195	+38 (from extracted declarations)

Benefits

1. Separation of Concerns: Type definitions, helpers, and main adapter now in separate files
2. Reusability: Helper classes can be used by other SQL adapters (future SQLite, MySQL variants)
3. Maintainability: Smaller files are easier to navigate and understand
4. Compile Time: Can include only needed headers (sql_types.hpp vs full adapter)
5. Testing: Helper classes can be unit tested independently

Impact

• ✅ No breaking changes to public API
• ✅ All includes properly updated
• ✅ Dialect enum reused from sql_connection.hpp
• ✅ Clean separation: types, helpers, adapter

Files Modified

• src/adapters/sql/sql_adapter_base.hpp - Reduced from 157 to 94 lines
• src/adapters/sql/sql_types.hpp - NEW (49 lines)
• src/adapters/sql/sql_adapter_helpers.hpp - NEW (52 lines)

Implementation Pattern

This split follows the pattern:

1. Types layer - Basic data structures (sql_types.hpp)
2. Helpers layer - Static utility functions (sql_adapter_helpers.hpp)
3. Adapter layer - Main business logic (sql_adapter_base.hpp)

Can be applied to other large headers in the codebase.