added alter table command to fluent query builder (progress)

source/orm/orm/schema.cpp

@@ -2,11 +2,19 @@
 
 #include "matador/orm/error_code.hpp"
 #include "matador/orm/session.hpp"
+
 #include "matador/query/query.hpp"
 
+#include "matador/sql/backend_provider.hpp"
 #include "matador/sql/connection_pool.hpp"
+#include "matador/sql/dialect.hpp"
 
 namespace matador::orm {
+schema::schema(sql::connection_pool& pool)
+: repo_(sql::backend_provider::instance().connection_dialect(pool.info().type).default_schema_name())
+, pool_(pool) {
+}
+
 schema::schema(sql::connection_pool &pool, const std::string& name)
 : repo_(name)
 , pool_(pool) {}
@@ -69,7 +77,38 @@ matador::utils::result<void, matador::utils::error> matador::orm::schema::create
 }
 
 matador::utils::result<void, matador::utils::error> matador::orm::schema::drop() const {
-  return utils::ok<void>();
+    std::vector<std::string> drop_sql_commands;
+    auto c = pool_.acquire();
+    for (const auto &node: repo_) {
+        auto ctx = query::query::drop()
+          .table(node->name())
+          .compile(*c);
+
+        drop_sql_commands.push_back(ctx.sql);
+        // determine constraints and drop them
+        for (auto it = node->info().endpoint_begin(); it != node->info().endpoint_end(); ++it) {
+            const auto ctx = query::query::alter()
+                .table( "" )
+                .add_constraint( it->second->node().name() )
+                .foreign_key( "" )
+                .references( "" ).compile(*c);
+
+        }
+        // for ( const auto& [sql, command] : ctx.additional_commands ) {
+        //     if (auto result = c->execute(ctx.sql); !result) {
+        //         return utils::failure(result.err());
+        //     }
+        // }
+    }
+
+    // execute additional commands (e.g. ALTER TABLE ADD FK)
+    for (const auto &sql: drop_sql_commands) {
+        std::cout << sql << std::endl;
+        if (auto result = c->execute(sql); !result) {
+            return utils::failure(result.err());
+        }
+    }
+    return utils::ok<void>();
 }
 
 matador::utils::result<void, matador::utils::error> matador::orm::schema::drop_table(const std::string& table_name) const {