added mysql backend

backends/postgres/include/postgres_connection.hpp

@@ -35,7 +35,7 @@ public:
 
   sql::record describe(const std::string& table) override;
 
-  bool exists(const std::string &table_name) override;
+  bool exists(const std::string &schema_name, const std::string &table_name) override;
 
 private:
   [[nodiscard]] static std::string generate_statement_name(const sql::query_context &query) ;

backends/postgres/include/postgres_statement.hpp

@@ -12,7 +12,7 @@ namespace matador::backends::postgres {
 class postgres_statement final : public sql::statement_impl
 {
 public:
-  postgres_statement(PGconn *db, PGresult *result, const std::string &name, const sql::query_context &query);
+  postgres_statement(PGconn *db, PGresult *result, std::string name, const sql::query_context &query);
 
   size_t execute() override;
   std::unique_ptr<sql::query_result_impl> fetch() override;

backends/postgres/src/postgres_connection.cpp

@@ -161,9 +161,9 @@ sql::record postgres_connection::describe(const std::string &table)
   return std::move(prototype);
 }
 
-bool postgres_connection::exists(const std::string &table_name)
+bool postgres_connection::exists(const std::string &schema_name, const std::string &table_name)
 {
-  std::string stmt("SELECT 1 FROM information_schema.tables WHERE table_schema = 'public' AND table_name = '" + table_name + "'");
+  std::string stmt("SELECT 1 FROM information_schema.tables WHERE table_schema = '" + schema_name + "' AND table_name = '" + table_name + "'");
 
   PGresult *res = PQexec(conn_, stmt.c_str());
 

backends/postgres/src/postgres_statement.cpp

@@ -4,11 +4,11 @@
 
 namespace matador::backends::postgres {
 
-postgres_statement::postgres_statement(PGconn *db, PGresult *result, const std::string &name, const sql::query_context &query)
+postgres_statement::postgres_statement(PGconn *db, PGresult *result, std::string name, const sql::query_context &query)
 : statement_impl(query)
 , db_(db)
 , result_(result)
-, name_(name)
+, name_(std::move(name))
 , binder_(query_.bind_vars.size())
 {}