implemented prepared statement for postgres and sqlite

backends/postgres/src/postgres_connection.cpp

@@ -1,13 +1,17 @@
 #include "postgres_connection.hpp"
 #include "postgres_error.hpp"
 #include "postgres_result_reader.hpp"
+#include "postgres_statement.hpp"
 
 #include "matador/sql/record.hpp"
 
 #include <iostream>
+#include <sstream>
 
 namespace matador::backends::postgres {
 
+postgres_connection::string_to_int_map postgres_connection::statement_name_map_{};
+
 postgres_connection::postgres_connection(const sql::connection_info &info)
 : connection_impl(info) {}
 
@@ -47,20 +51,41 @@ std::unique_ptr<sql::query_result_impl> postgres_connection::fetch(const std::st
   throw_postgres_error(res, conn_, "postgres", stmt);
 
   sql::record prototype;
-  auto ncol = PQnfields(res);
-  for (int i = 0; i < ncol; ++i) {
+  auto num_col = PQnfields(res);
+  for (int i = 0; i < num_col; ++i) {
     const char *col_name = PQfname(res, i);
     auto type = PQftype(res, i);
     auto size = PQfmod(res, i);
-    std::cout << "column " << col_name << ", type " << type << " (size: " << size << ")\n";
+//    std::cout << "column " << col_name << ", type " << type << " (size: " << size << ")\n";
     prototype.append({col_name});
   }
   return std::move(std::make_unique<sql::query_result_impl>(std::make_unique<postgres_result_reader>(res), std::move(prototype)));
 }
 
-void postgres_connection::prepare(const std::string &stmt)
+std::string postgres_connection::generate_statement_name(const sql::query_context &query)
 {
+  std::stringstream name;
+  name << query.table_name << "_" << query.command_name;
+  auto result = postgres_connection::statement_name_map_.find(name.str());
 
+  if (result == postgres_connection::statement_name_map_.end()) {
+    result = postgres_connection::statement_name_map_.insert(std::make_pair(name.str(), 0)).first;
+  }
+
+  name << "_" << ++result->second;
+
+  return name.str();
+}
+
+std::unique_ptr<sql::statement_impl> postgres_connection::prepare(sql::query_context context)
+{
+  auto statement_name = postgres_connection::generate_statement_name(context);
+
+  PGresult *result = PQprepare(conn_, statement_name.c_str(), context.sql.c_str(), static_cast<int>(context.bind_vars.size()), nullptr);
+
+  throw_postgres_error(result, conn_, "postgres", context.sql);
+
+  return std::make_unique<postgres_statement>(conn_, result, statement_name, std::move(context));
 }
 
 size_t postgres_connection::execute(const std::string &stmt)

backends/postgres/src/postgres_dialect.cpp

@@ -1,7 +1,15 @@
 #include "postgres_dialect.hpp"
 
+#include "matador/sql/dialect_builder.hpp"
+
 [[maybe_unused]] const matador::sql::dialect* get_dialect() {
   using namespace matador::sql;
-  const static dialect d{};
+  const static dialect d = dialect_builder::builder()
+    .create()
+    .with_placeholder_func([](size_t index) {
+      return "$" + std::to_string(index);
+    })
+    .with_default_schema_name("public")
+    .build();
   return &d;
 }

backends/postgres/src/postgres_parameter_binder.cpp

@@ -0,0 +1,142 @@
+#include "postgres_parameter_binder.h"
+
+namespace matador::backends::postgres {
+
+namespace detail {
+
+template < class T >
+void bind_value(std::vector<std::string> &strings, std::vector<const char*> &params, size_t index, T &x)
+{
+  strings[index] = std::to_string(x);
+  params[index] = strings[index].c_str();
+}
+
+template <>
+void bind_value(std::vector<std::string> &strings, std::vector<const char*> &params, size_t index, char &x)
+{
+  strings[index] = std::to_string(x);
+  params[index] = strings[index].data();
+}
+
+template <>
+void bind_value(std::vector<std::string> &strings, std::vector<const char*> &params, size_t index, unsigned char &x)
+{
+  strings[index] = std::to_string(x);
+  params[index] = strings[index].data();
+}
+
+//template <>
+//void bind_value(std::vector<std::string> &strings, std::vector<const char*> &params, size_t &index, const matador::date &x)
+//{
+//  strings[index] = matador::to_string(x, date_format::ISO8601);
+//  params[index] = strings[index].c_str();
+//  ++index;
+//}
+//
+//template <>
+//void bind_value(std::vector<std::string> &strings, std::vector<const char*> &params, size_t &index, const matador::time &x)
+//{
+//  strings[index] = matador::to_string(x, "%Y-%m-%d %T.%f");
+//  params[index] = strings[index].c_str();
+//  ++index;
+//}
+
+}
+
+postgres_parameter_binder::postgres_parameter_binder(size_t size)
+: strings_(size)
+, params_(size)
+{}
+
+void postgres_parameter_binder::bind(size_t pos, char i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, short i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, int i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, long i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, long long int i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, unsigned char i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, unsigned short i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, unsigned int i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, unsigned long i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, unsigned long long int i)
+{
+  detail::bind_value(strings_, params_, pos, i);
+}
+
+void postgres_parameter_binder::bind(size_t pos, bool b)
+{
+  detail::bind_value(strings_, params_, pos, b);
+}
+
+void postgres_parameter_binder::bind(size_t pos, float d)
+{
+  detail::bind_value(strings_, params_, pos, d);
+}
+
+void postgres_parameter_binder::bind(size_t pos, double d)
+{
+  detail::bind_value(strings_, params_, pos, d);
+}
+
+void postgres_parameter_binder::bind(size_t pos, const char *str)
+{
+  params_[pos] = str;
+}
+
+void postgres_parameter_binder::bind(size_t pos, const char *str, size_t size)
+{
+  params_[pos] = str;
+}
+
+void postgres_parameter_binder::bind(size_t pos, const std::string &str)
+{
+  strings_[pos] = str;
+  params_[pos] = strings_[pos].c_str();
+}
+
+void postgres_parameter_binder::bind(size_t pos, const std::string &str, size_t size)
+{
+  bind(pos, str);
+}
+
+const std::vector<const char *> &postgres_parameter_binder::params() const
+{
+  return params_;
+}
+
+}

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_;
+}
+
+}