feat(db): add SQLite migration SQL generation

.github/workflows/db-strict-ci.yml

@@ -14,6 +14,7 @@ on:
       - "include/**"
       - "src/**"
       - "examples/**"
+      - "tests/**"
       - "tools/**"
       - "README.md"
       - "LICENSE"
@@ -32,6 +33,7 @@ on:
       - "include/**"
       - "src/**"
       - "examples/**"
+      - "tests/**"
       - "tools/**"
       - "README.md"
       - "LICENSE"
@@ -189,6 +191,7 @@ jobs:
             -DCMAKE_BUILD_TYPE=Debug \
             -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
             -DVIX_ENABLE_SANITIZERS=OFF \
+            -DVIX_DB_BUILD_TESTS=ON \
             -DVIX_DB_BUILD_EXAMPLES=${{ matrix.examples }} \
             -DVIX_DB_USE_MYSQL=${{ matrix.mysql }} \
             -DVIX_DB_REQUIRE_MYSQL=OFF \
@@ -205,6 +208,10 @@ jobs:
         run: |
           cmake --build build -j"${BUILD_JOBS}"
 
+      - name: Test
+        run: |
+          ctest --test-dir build --output-on-failure
+
       - name: Print executables
         run: |
           find build -type f -executable | sort || true

CMakeLists.txt

@@ -224,6 +224,8 @@ set(VIX_DB_PUBLIC_HEADERS
   include/vix/db/mig/Migration.hpp
   include/vix/db/mig/MigrationsRunner.hpp
   include/vix/db/mig/FileMigrationsRunner.hpp
+  include/vix/db/mig/sql/MySqlGenerator.hpp
+  include/vix/db/mig/sql/SQLiteGenerator.hpp
 )
 
 set(VIX_DB_SOURCES
@@ -235,6 +237,7 @@ set(VIX_DB_SOURCES
   src/schema/Json.cpp
   src/mig/diff/Diff.cpp
   src/mig/sql/MySqlGenerator.cpp
+  src/mig/sql/SQLiteGenerator.cpp
 )
 
 # MySQL driver sources
@@ -426,6 +429,37 @@ if (VIX_DB_BUILD_EXAMPLES)
   add_subdirectory(examples)
 endif()
 
+# ------------------------------------------------------------------------------
+# Tests
+# ------------------------------------------------------------------------------
+if (VIX_DB_BUILD_TESTS)
+  enable_testing()
+
+  if (VIX_DB_HAS_SQLITE)
+    add_executable(vix_db_sql_generator_tests
+      tests/sql_generator_tests.cpp
+      tools/migrator/MakeMigrations.cpp
+    )
+
+    target_link_libraries(vix_db_sql_generator_tests PRIVATE vix::db)
+    target_compile_features(vix_db_sql_generator_tests PRIVATE cxx_std_20)
+
+    if (MSVC)
+      target_compile_options(vix_db_sql_generator_tests PRIVATE ${_WARNINGS_MSVC})
+    else()
+      target_compile_options(vix_db_sql_generator_tests PRIVATE ${_WARNINGS_GNU})
+    endif()
+
+    if (COMMAND vix_enable_sanitizers)
+      vix_enable_sanitizers(vix_db_sql_generator_tests)
+    endif()
+
+    add_test(NAME vix_db_sql_generator_tests COMMAND vix_db_sql_generator_tests)
+  else()
+    message(STATUS "[vix_db] tests requested but SQLite is disabled; SQL execution tests skipped.")
+  endif()
+endif()
+
 # ------------------------------------------------------------------------------
 # Install / export via umbrella export-set "VixTargets"
 # ------------------------------------------------------------------------------

README.md

@@ -198,6 +198,16 @@ vix build --clean
 vix build --preset release
 ```
 
+## Migration SQL generation
+
+Generate file-based migrations from a schema snapshot with either MySQL or SQLite SQL:
+
+```bash
+vix_db_migrator makemigrations --new ./schema.new.json --snapshot ./schema.json --dir ./migrations --name create_users --dialect sqlite
+```
+
+SQLite migration generation emits native DDL for table, column, and index operations. Unsupported SQLite `ADD COLUMN` forms, such as adding primary-key, unique, autoincrement, or required columns without defaults, fail before writing migration files. Down migrations for dropped columns use SQLite 3.35+ `DROP COLUMN` syntax.
+
 ## Tests
 
 Build all targets first, then run tests:

include/vix/db/mig/sql/SQLiteGenerator.hpp

@@ -0,0 +1,50 @@
+/**
+ *
+ *  @file SQLiteGenerator.hpp
+ *  @author Gaspard Kirira
+ *
+ *  Copyright 2025, Gaspard Kirira.
+ *  All rights reserved.
+ *  https://github.com/vixcpp/vix
+ *
+ *  Use of this source code is governed by a MIT license
+ *  that can be found in the License file.
+ *
+ *  Vix.cpp
+ */
+#ifndef VIX_DB_MIG_SQL_SQLITE_GENERATOR_HPP
+#define VIX_DB_MIG_SQL_SQLITE_GENERATOR_HPP
+
+#include <vix/db/mig/diff/Op.hpp>
+
+#include <string>
+#include <vector>
+
+namespace vix::db::mig::sql
+{
+  /**
+   * @brief Generate SQLite SQL statements for applying a migration.
+   *
+   * Converts portable migration operations into SQLite DDL. Unsupported
+   * SQLite alterations fail with std::runtime_error before any SQL script
+   * is returned.
+   *
+   * @param ops Ordered list of migration operations.
+   * @return SQL script for the "up" migration.
+   */
+  std::string to_sqlite_up(const std::vector<vix::db::mig::diff::Op> &ops);
+
+  /**
+   * @brief Generate SQLite SQL statements for reverting a migration.
+   *
+   * Produces the inverse SQL script in reverse operation order.
+   * SQLite DROP COLUMN is emitted using the native SQLite 3.35+ syntax.
+   *
+   * @param ops Ordered list of migration operations.
+   * @return SQL script for the "down" migration.
+   */
+  std::string to_sqlite_down(const std::vector<vix::db::mig::diff::Op> &ops);
+
+} // namespace vix::db::mig::sql
+
+#endif // VIX_DB_MIG_SQL_SQLITE_GENERATOR_HPP

src/mig/diff/Diff.cpp

@@ -24,25 +24,26 @@ namespace vix::db::mig::diff
     auto A = map_tables(from);
     auto B = map_tables(to);
 
-    // 1) Drop tables missing in 'to'
-    for (const auto &[name, ta] : A)
+    // 1) Drop tables missing in 'to', preserving source schema order.
+    for (const auto &table : from.tables)
     {
-      if (!B.count(name))
-        ops.push_back(DropTable{*ta});
+      if (!B.count(table.name))
+        ops.push_back(DropTable{table});
     }
 
-    // 2) Create tables new in 'to'
-    for (const auto &[name, tb] : B)
+    // 2) Create tables new in 'to', preserving target schema order.
+    for (const auto &targetTable : to.tables)
     {
+      const auto &name = targetTable.name;
       if (!A.count(name))
       {
-        ops.push_back(CreateTable{*tb});
+        ops.push_back(CreateTable{targetTable});
         continue;
       }
 
       // 3) Same table: diff columns + indexes
       const auto *oldT = A.at(name);
-      const auto *newT = tb;
+      const auto *newT = &targetTable;
 
       // Columns: drops
       for (const auto &c_old : oldT->columns)
@@ -52,7 +53,7 @@ namespace vix::db::mig::diff
       }
 
       // Columns: adds
-      for (const auto &c_new : newT->columns)
+      for (const auto &c_new : targetTable.columns)
       {
         if (!oldT->findColumn(c_new.name))
           ops.push_back(AddColumn{name, c_new});
@@ -66,7 +67,7 @@ namespace vix::db::mig::diff
       }
 
       // Indexes: adds
-      for (const auto &i_new : newT->indexes)
+      for (const auto &i_new : targetTable.indexes)
       {
         if (!oldT->findIndex(i_new.name))
           ops.push_back(CreateIndex{name, i_new});