Rename raw_sql to sql_raw; add execute(sql_raw)

- Rename raw_sql class to sql_raw throughout (database.hpp, tests)
- Add execute(sql_raw) overload returning std::expected<void, std::string>
- Remove sql.hpp (split into sql_ddl.hpp, sql_dml.hpp, sql_dql.hpp)
- Update ds_mysql.hpp umbrella header and docs to reflect the split

Author: Pierre-Luc Gagné

docs/DEVELOPMENT.md

@@ -27,7 +27,7 @@ DSMySQL is a header-only library. All functionality lives in `lib/include/ds_mys
 1. Create a new header under `lib/include/ds_mysql/`
 2. Use `#pragma once`
 3. Put all code in the `ds_mysql` namespace
-4. Include it transitively through `ds_mysql/database.hpp`, `ds_mysql/metadata.hpp`, or `ds_mysql/sql.hpp` if appropriate (those three are pulled in by the `ds_mysql/ds_mysql.hpp` umbrella header)
+4. Include it transitively through `ds_mysql/database.hpp`, `ds_mysql/metadata.hpp`, `ds_mysql/sql_ddl.hpp`, `ds_mysql/sql_dml.hpp`, or `ds_mysql/sql_dql.hpp` if appropriate (these are pulled in by the `ds_mysql/ds_mysql.hpp` umbrella header)
 
 ## Adding Unit Tests
 

docs/QUICKREF.md

@@ -47,10 +47,12 @@ DSMySQL/
 ## Key Headers
 
 | Header | Purpose |
-|--------|---------|
+| ------ | ------- |
 | `ds_mysql.hpp` | **Umbrella header** — include this to get everything |
 | `ds_mysql/database.hpp` | MySQL connection & queries |
-| `ds_mysql/sql.hpp` | SQL query builder (includes helpers & MySQL features) |
+| `ds_mysql/sql_ddl.hpp` | DDL query builder (CREATE / DROP / ALTER / ...) |
+| `ds_mysql/sql_dml.hpp` | DML query builder (INSERT / UPDATE / DELETE / DESCRIBE / ...) |
+| `ds_mysql/sql_dql.hpp` | DQL query builder (SELECT / projections / expressions / ...) |
 | `ds_mysql/sql_temporal.hpp` | Temporal types: `datetime_type`, `timestamp_type`, `time_type` |
 | `ds_mysql/metadata.hpp` | MySQL information_schema types |
 | `ds_mysql/column_field.hpp` | Typed column descriptors |
@@ -61,7 +63,7 @@ DSMySQL/
 ## Environment Variables (Integration Tests)
 
 | Variable | Default |
-|----------|---------|
+| -------- | ------- |
 | `DS_MYSQL_TEST_HOST` | `127.0.0.1` |
 | `DS_MYSQL_TEST_PORT` | `3307` |
 | `DS_MYSQL_TEST_DATABASE` | `ds_mysql_test` |

lib/include/ds_mysql/database.hpp

@@ -26,7 +26,8 @@ namespace ds_mysql {
 // ===================================================================
 // raw_sql — explicit escape hatch for raw SQL strings.
 //
-// Use this only when none of the typed builders in sql.hpp cover your
+// Use this only when none of the typed builders in sql_ddl.hpp, sql_dml.hpp,
+// or sql_dql.hpp cover your
 // case. Always returns std::expected<std::vector<std::vector<std::optional<std::string>>>, std::string>.
 // Each inner vector is a row; each element is a nullable cell value.
 // DDL / DML statements that produce no result set return an empty outer vector.
@@ -123,7 +124,8 @@ void validate_table_fields(std::vector<describe_row_type> const& rows, std::stri
 // mysql_database — thin wrapper around the MySQL C API.
 //
 // Provides type-safe query() and execute() methods that accept any builder
-// from sql.hpp, plus a raw_sql overload for unhandled cases.
+// from sql_ddl.hpp, sql_dml.hpp, and sql_dql.hpp, plus a raw_sql overload
+// for unhandled cases.
 //
 // Factory methods:
 //   mysql_database::connect(host, database, credentials, port)

lib/include/ds_mysql/ds_mysql.hpp

@@ -4,12 +4,14 @@
 //
 // Transitively provides:
 //   database.hpp        — database connection, query execution, result sets
-//   sql.hpp             — query builder (SELECT / INSERT / UPDATE / DELETE / ...) and helpers
+//   sql_ddl.hpp         — DDL query builder (CREATE / DROP / ALTER / ...)
+//   sql_dml.hpp         — DML query builder (INSERT / UPDATE / DELETE / DESCRIBE / ...)
+//   sql_dql.hpp         — DQL query builder (SELECT / projections / expressions / ...)
 //   metadata.hpp        — runtime metadata helpers (column info, schema introspection)
 //
 // All other library headers (column_field, schema_generator, sql_identifiers,
 // sql_temporal, sql_varchar, sql_text, config, credentials, …) are
-// pulled in transitively by the three headers above.
+// pulled in transitively by the headers above.
 
 #include "ds_mysql/database.hpp"
 #include "ds_mysql/metadata.hpp"