implemented prepared statement for postgres and sqlite

backends/postgres/src/postgres_statement.cpp

@@ -0,0 +1,40 @@
+#include "postgres_statement.hpp"
+#include "postgres_error.hpp"
+#include "postgres_result_reader.hpp"
+
+namespace matador::backends::postgres {
+
+postgres_statement::postgres_statement(PGconn *db, PGresult *result, const std::string &name, const sql::query_context &query)
+: statement_impl(query)
+, db_(db)
+, result_(result)
+, name_(name)
+, binder_(query_.bind_vars.size())
+{}
+
+size_t postgres_statement::execute()
+{
+  PGresult *res = PQexecPrepared(db_, name_.c_str(), static_cast<int>(binder_.params().size()), binder_.params().data(), nullptr, nullptr, 0);
+
+  throw_postgres_error(res, db_, "postgres", query_.sql);
+
+  return std::stoul(PQcmdTuples(res));
+}
+
+std::unique_ptr<sql::query_result_impl> postgres_statement::fetch()
+{
+  PGresult *res = PQexecPrepared(db_, name_.c_str(), static_cast<int>(binder_.params().size()), binder_.params().data(), nullptr, nullptr, 0);
+
+  throw_postgres_error(res, db_, "postgres", query_.sql);
+
+  return std::move(std::make_unique<sql::query_result_impl>(std::make_unique<postgres_result_reader>(res), std::move(query_.prototype)));
+}
+
+void postgres_statement::reset() {}
+
+sql::parameter_binder& postgres_statement::binder()
+{
+  return binder_;
+}
+
+}