moved parameter_binder from member to parameter to bind, execute and fetch methods

backends/postgres/include/postgres_parameter_binder.h

@@ -1,14 +1,13 @@
 #ifndef QUERY_POSTGRES_PARAMETER_BINDER_H
 #define QUERY_POSTGRES_PARAMETER_BINDER_H
 
-#include "matador/utils/attribute_writer.hpp"
+#include "matador/sql/interface/parameter_binder.hpp"
 
 #include <vector>
 
 namespace matador::backends::postgres {
 
-class postgres_parameter_binder final : public utils::attribute_writer
+class postgres_parameter_binder final : public sql::interface::parameter_binder {
-{
 public:
   struct bind_data {
     explicit bind_data(size_t size);

backends/postgres/include/postgres_statement.hpp

@@ -2,8 +2,7 @@
 #define QUERY_POSTGRES_STATEMENT_HPP
 
 #include "matador/sql/interface/statement_impl.hpp"
-
+#include "matador/sql/interface/parameter_binder.hpp"
-#include "postgres_parameter_binder.h"
 
 #include <libpq-fe.h>
 
@@ -14,18 +13,17 @@ class postgres_statement final : public sql::statement_impl
 public:
   postgres_statement(PGconn *db, std::string name, const sql::query_context &query);
 
-  utils::result<size_t, utils::error> execute() override;
+  utils::result<size_t, utils::error> execute(const sql::interface::parameter_binder& bindings) override;
-  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch() override;
+  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch(const sql::interface::parameter_binder& bindings) override;
   void reset() override;
+
 protected:
-  utils::attribute_writer& binder() override;
+  [[nodiscard]] std::unique_ptr<utils::attribute_writer> create_binder() const override;
 
 private:
   PGconn *db_{nullptr};
 
   std::string name_;
-
-  postgres_parameter_binder binder_;
 };
 
 }

backends/postgres/src/postgres_parameter_binder.cpp

@@ -53,7 +53,7 @@ postgres_parameter_binder::bind_data::bind_data(const size_t size)
 , formats(size)
 {}
 
-postgres_parameter_binder::postgres_parameter_binder(size_t size)
+postgres_parameter_binder::postgres_parameter_binder(const size_t size)
 : bind_data_(size)
 {}
 

backends/postgres/src/postgres_statement.cpp

@@ -1,5 +1,6 @@
 #include "postgres_statement.hpp"
 #include "postgres_error.hpp"
+#include "postgres_parameter_binder.h"
 #include "postgres_result_reader.hpp"
 
 namespace matador::backends::postgres {
@@ -8,17 +9,19 @@ postgres_statement::postgres_statement(PGconn *db, std::string name, const sql::
 : statement_impl(query)
 , db_(db)
 , name_(std::move(name))
-, binder_(query_.bind_vars.size())
 {}
 
-utils::result<size_t, utils::error> postgres_statement::execute()
+utils::result<size_t, utils::error> postgres_statement::execute(const sql::interface::parameter_binder& bindings) {
-{
+  const auto* postgres_bindings = dynamic_cast<const postgres_parameter_binder*>(&bindings);
+  if (!postgres_bindings) {
+    return utils::failure(utils::error(sql::error_code::EXECUTE_FAILED, "Failed to cast bindings to postgres bindings"));
+  }
   PGresult *res = PQexecPrepared(db_,
       name_.c_str(),
-      static_cast<int>(binder_.params().values.size()),
+      static_cast<int>(postgres_bindings->params().values.size()),
-      binder_.params().values.data(),
+      postgres_bindings->params().values.data(),
-      binder_.params().lengths.data(),
+      postgres_bindings->params().lengths.data(),
-      binder_.params().formats.data(),
+      postgres_bindings->params().formats.data(),
       0);
 
   if (is_result_error(res)) {
@@ -30,17 +33,20 @@ utils::result<size_t, utils::error> postgres_statement::execute()
     return utils::ok(static_cast<size_t>(0));
   }
 
-  return utils::ok(static_cast<size_t>(std::stoul(tuples)));
+  return utils::ok((std::stoul(tuples)));
 }
 
-utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_statement::fetch()
+utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_statement::fetch(const sql::interface::parameter_binder& bindings) {
-{
+  const auto* postgres_bindings = dynamic_cast<const postgres_parameter_binder*>(&bindings);
+  if (!postgres_bindings) {
+    return utils::failure(utils::error(sql::error_code::EXECUTE_FAILED, "Failed to cast bindings to postgres bindings"));
+  }
   PGresult *res = PQexecPrepared(db_,
       name_.c_str(),
-      static_cast<int>(binder_.params().values.size()),
+      static_cast<int>(postgres_bindings->params().values.size()),
-      binder_.params().values.data(),
+      postgres_bindings->params().values.data(),
-      binder_.params().lengths.data(),
+      postgres_bindings->params().lengths.data(),
-      binder_.params().formats.data(),
+      postgres_bindings->params().formats.data(),
       0);
 
   if (is_result_error(res)) {
@@ -52,9 +58,7 @@ utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_st
 
 void postgres_statement::reset() {}
 
-utils::attribute_writer& postgres_statement::binder()
+std::unique_ptr<utils::attribute_writer> postgres_statement::create_binder() const {
-{
+  return std::make_unique<postgres_parameter_binder>(query_.bind_vars.size());
-  return binder_;
 }
-
 }

include/matador/sql/interface/parameter_binder.hpp

@@ -1,37 +1,11 @@
 #ifndef QUERY_PARAMETER_BINDER_HPP
 #define QUERY_PARAMETER_BINDER_HPP
 
-#include "matador/utils/types.hpp"
+#include "matador/utils/attribute_writer.hpp"
-
-#include <string>
-#include <cstring>
 
 namespace matador::sql::interface {
 
-class parameter_binder
+using parameter_binder = utils::attribute_writer;
-{
-public:
-  virtual ~parameter_binder() = default;
-
-  virtual void bind(size_t pos, int8_t) = 0;
-  virtual void bind(size_t pos, int16_t) = 0;
-  virtual void bind(size_t pos, int32_t) = 0;
-  virtual void bind(size_t pos, int64_t) = 0;
-  virtual void bind(size_t pos, uint8_t) = 0;
-  virtual void bind(size_t pos, uint16_t) = 0;
-  virtual void bind(size_t pos, uint32_t) = 0;
-  virtual void bind(size_t pos, uint64_t) = 0;
-  virtual void bind(size_t pos, bool) = 0;
-  virtual void bind(size_t pos, float) = 0;
-  virtual void bind(size_t pos, double) = 0;
-  virtual void bind(size_t pos, const char *) = 0;
-  virtual void bind(size_t pos, const char *, size_t size) = 0;
-  virtual void bind(size_t pos, const std::string&) = 0;
-  virtual void bind(size_t pos, const std::string &x, size_t size) = 0;
-  virtual void bind(size_t pos, const utils::blob &) = 0;
-//  virtual void bind(size_t pos, const matador::time&) = 0;
-//  virtual void bind(size_t pos, const matador::date&) = 0;
-};
 
 }
 

include/matador/sql/interface/statement_impl.hpp

@@ -3,6 +3,7 @@
 
 #include "matador/sql/query_context.hpp"
 #include "matador/sql/internal/query_result_impl.hpp"
+#include "matador/sql/interface/parameter_binder.hpp"
 #include "matador/sql/object_parameter_binder.hpp"
 
 #include "matador/utils/data_type_traits.hpp"
@@ -21,24 +22,23 @@ protected:
 public:
   virtual ~statement_impl() = default;
 
-  virtual utils::result<size_t, utils::error> execute() = 0;
+  virtual utils::result<size_t, utils::error> execute(const interface::parameter_binder& bindings) = 0;
-  virtual utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch() = 0;
+  virtual utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(const interface::parameter_binder& bindings) = 0;
 
   template < class Type >
-  void bind_object(Type &obj)
+  void bind_object(Type &obj, const interface::parameter_binder& bindings) {
-  {
     object_parameter_binder object_binder_;
     object_binder_.reset(start_index());
-    object_binder_.bind(obj, binder());
+    object_binder_.bind(obj, bindings);
   }
 
   template < class Type >
-  void bind(const size_t pos, Type &val) {
+  void bind(const size_t pos, Type &val, const interface::parameter_binder& bindings) {
-    utils::data_type_traits<Type>::bind_value(binder(), adjust_index(pos), val);
+    utils::data_type_traits<Type>::bind_value(bindings, adjust_index(pos), val);
   }
 
-  void bind(size_t pos, const char *value, size_t size);
+  void bind(size_t pos, const char *value, size_t size, interface::parameter_binder& bindings) const;
-  void bind(size_t pos, std::string &val, size_t size);
+  void bind(size_t pos, std::string &val, size_t size, interface::parameter_binder& bindings) const;
 
   virtual void reset() = 0;
 
@@ -46,12 +46,13 @@ public:
   [[nodiscard]] bool is_valid_host_var(const std::string &host_var, size_t pos) const;
 
 protected:
-  virtual utils::attribute_writer& binder() = 0;
   [[nodiscard]] virtual size_t start_index() const;
   [[nodiscard]] virtual size_t adjust_index(size_t index) const;
+  [[nodiscard]] virtual std::unique_ptr<utils::attribute_writer> create_binder() const = 0;
 
 protected:
   friend class statement;
+  friend class statement_proxy;
 
   query_context query_;
 };

include/matador/sql/interface/statement_proxy.hpp

@@ -2,6 +2,7 @@
 #define STATEMENT_PROXY_HPP
 
 #include "matador/sql/interface/statement_impl.hpp"
+#include "matador/sql/interface/parameter_binder.hpp"
 
 namespace matador::sql {
 class statement_proxy {
@@ -11,22 +12,24 @@ protected:
 public:
   virtual ~statement_proxy() = default;
 
-  virtual utils::result<size_t, utils::error> execute() = 0;
+  virtual utils::result<size_t, utils::error> execute(interface::parameter_binder& bindings) = 0;
-  virtual utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch() = 0;
+  virtual utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(interface::parameter_binder& bindings) = 0;
 
   template<class Type>
-  void bind(const Type &obj) {
+  void bind(const Type &obj, const interface::parameter_binder& bindings) {
-    statement_->bind_object(obj);
+    statement_->bind_object(obj, bindings);
   }
   template<typename Type>
-  void bind(size_t pos, Type &value) {
+  void bind(size_t pos, Type &value, const interface::parameter_binder& bindings) {
-    statement_->bind(pos, value);
+    statement_->bind(pos, value, bindings);
   }
-  void bind(size_t pos, const char *value, size_t size) const;
+  void bind(size_t pos, const char *value, size_t size, interface::parameter_binder& bindings) const;
-  void bind(size_t pos, std::string &val, size_t size) const;
+  void bind(size_t pos, std::string &val, size_t size, interface::parameter_binder& bindings) const;
 
   void reset() const;
 
+  [[nodiscard]] std::unique_ptr<utils::attribute_writer> create_binder() const;
+
 protected:
   std::unique_ptr<statement_impl> statement_;
 };

include/matador/sql/object_parameter_binder.hpp

@@ -9,8 +9,6 @@
 #include "matador/utils/foreign_attributes.hpp"
 #include "matador/utils/primary_key_attribute.hpp"
 
-#include <string>
-
 namespace matador::sql {
 
 namespace detail {
@@ -61,8 +59,7 @@ private:
 
 }
 
-class object_parameter_binder
+class object_parameter_binder {
-{
 public:
   template<class Type>
   void bind(Type &obj, utils::attribute_writer &binder) {

include/matador/sql/statement.hpp

@@ -5,6 +5,7 @@
 #include "matador/sql/query_result.hpp"
 
 #include "matador/sql/interface/statement_proxy.hpp"
+#include "matador/sql/interface/parameter_binder.hpp"
 
 #include "matador/utils/error.hpp"
 #include "matador/utils/result.hpp"
@@ -38,10 +39,7 @@ public:
    *
    * @param x The statement to move from
    */
-  statement(statement &&x) noexcept
+  statement(statement &&x) noexcept;
-    : statement_proxy_(std::move(x.statement_proxy_))
-      , logger_(std::move(x.logger_)) {
-  }
 
   /**
    * Assignment move constructor for statement
@@ -49,14 +47,10 @@ public:
    * @param x The statement to move from
    * @return Reference to this
    */
-  statement &operator=(statement &&x) noexcept {
+  statement &operator=(statement &&x) noexcept;
-    statement_proxy_ = std::move(x.statement_proxy_);
-    logger_ = std::move(x.logger_);
-    return *this;
-  }
 
-  statement(const statement &x) = default;
+  statement(const statement &x);
-  statement &operator=(const statement &x) = default;
+  statement &operator=(const statement &x);
 
   statement &bind(size_t pos, const char *value);
   statement &bind(size_t pos, std::string &val, size_t size);
@@ -134,24 +128,25 @@ private:
 
 private:
   std::shared_ptr<statement_proxy> statement_proxy_;
+  std::unique_ptr<utils::attribute_writer> bindings_;
   std::shared_ptr<abstract_sql_logger> logger_;
 };
 
 template<typename Type>
 statement &statement::bind(size_t pos, Type &value) {
-  statement_proxy_->bind(pos, value);
+  statement_proxy_->bind(pos, value, *bindings_);
   return *this;
 }
 
 template<class Type>
 statement &statement::bind(const Type &obj) {
-  statement_proxy_->bind(obj);
+  statement_proxy_->bind(obj, bindings_);
   return *this;
 }
 
 template<class Type>
 utils::result<query_result<Type>, utils::error> statement::fetch() {
-  return statement_proxy_->fetch().and_then([](std::unique_ptr<query_result_impl> &&value) {
+  return statement_proxy_->fetch(*bindings_).and_then([](std::unique_ptr<query_result_impl> &&value) {
     return utils::ok(query_result<Type>(std::forward<decltype(value)>(value)));
   });
 //  if (!result.is_ok()) {
@@ -162,7 +157,7 @@ utils::result<query_result<Type>, utils::error> statement::fetch() {
 
 template<class Type>
 utils::result<std::unique_ptr<Type>, utils::error> statement::fetch_one() {
-  auto result = statement_proxy_->fetch();
+  auto result = statement_proxy_->fetch(*bindings_);
   if (!result.is_ok()) {
     return utils::failure(result.err());
   }

source/orm/sql/connection.cpp

@@ -19,11 +19,11 @@ public:
   explicit connection_statement_proxy(std::unique_ptr<statement_impl>&& stmt)
   : statement_proxy(std::move(stmt)) {}
 
-  utils::result<size_t, utils::error> execute() override {
+  utils::result<size_t, utils::error> execute(interface::parameter_binder& bindings) override {
-    return statement_->execute();
+    return statement_->execute(bindings);
   }
-  utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch() override {
+  utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(interface::parameter_binder& bindings) override {
-    return statement_->fetch();
+    return statement_->fetch(bindings);
   }
 };
 

source/orm/sql/interface/statement_impl.cpp

@@ -6,35 +6,29 @@ statement_impl::statement_impl(query_context query)
 : query_(std::move(query))
 {}
 
-void statement_impl::bind(const size_t pos, const char *value, const size_t size)
+void statement_impl::bind(const size_t pos, const char *value, const size_t size, interface::parameter_binder& bindings) const {
-{
+  utils::data_type_traits<const char*>::bind_value(bindings, adjust_index(pos), value, size);
-  utils::data_type_traits<const char*>::bind_value(binder(), adjust_index(pos), value, size);
 }
 
-void statement_impl::bind(const size_t pos, std::string &val, const size_t size)
+void statement_impl::bind(const size_t pos, std::string &val, const size_t size, interface::parameter_binder& bindings) const {
-{
+  utils::data_type_traits<std::string>::bind_value(bindings, adjust_index(pos), val, size);
-  utils::data_type_traits<std::string>::bind_value(binder(), adjust_index(pos), val, size);
 }
 
-const std::vector<std::string> &statement_impl::bind_vars() const
+const std::vector<std::string> &statement_impl::bind_vars() const {
-{
   return query_.bind_vars;
 }
 
-bool statement_impl::is_valid_host_var(const std::string &host_var, const size_t pos) const
+bool statement_impl::is_valid_host_var(const std::string &host_var, const size_t pos) const {
-{
   const auto host_var_at_pos = bind_vars().at(pos);
 
   return host_var_at_pos == host_var;
 }
 
-size_t statement_impl::start_index() const
+size_t statement_impl::start_index() const {
-{
     return 0;
 }
 
-size_t statement_impl::adjust_index( size_t index ) const
+size_t statement_impl::adjust_index(const size_t index) const {
-{
     return index;
 }
 

source/orm/sql/interface/statement_proxy.cpp

@@ -4,14 +4,18 @@ namespace matador::sql {
 statement_proxy::statement_proxy(std::unique_ptr<statement_impl>&& stmt)
 : statement_(std::move(stmt)){}
 
-void statement_proxy::bind(const size_t pos, const char* value, const size_t size) const {
+void statement_proxy::bind(const size_t pos, const char* value, const size_t size, interface::parameter_binder& bindings) const {
-  statement_->bind(pos, value, size);
+  statement_->bind(pos, value, size, bindings);
 }
-void statement_proxy::bind(const size_t pos, std::string& val, const size_t size) const {
+void statement_proxy::bind(const size_t pos, std::string& val, const size_t size, interface::parameter_binder& bindings) const {
-  statement_->bind(pos, val, size);
+  statement_->bind(pos, val, size, bindings);
 }
 
 void statement_proxy::reset() const {
   statement_->reset();
 }
+
+std::unique_ptr<utils::attribute_writer> statement_proxy::create_binder() const {
+  return statement_->create_binder();
+}
 }

source/orm/sql/statement.cpp

@@ -11,20 +11,47 @@ statement::statement(const std::shared_ptr<statement_proxy>& proxy, logger_ptr
 : statement_proxy_(proxy)
 , logger_(std::move(logger)){}
 
-statement &statement::bind(const size_t pos, const char *value) {
+statement::statement(statement&& x) noexcept
-  statement_proxy_->bind(pos, value, strlen(value));
+: statement_proxy_(std::move(x.statement_proxy_))
+, bindings_(std::move(x.bindings_))
+, logger_(std::move(x.logger_)) {
+}
+
+statement& statement::operator=(statement&& x) noexcept {
+  statement_proxy_ = std::move(x.statement_proxy_);
+  bindings_ = std::move(x.bindings_);
+  logger_ = std::move(x.logger_);
   return *this;
 }
 
-statement &statement::bind(const size_t pos, std::string &val, const size_t size)
+statement::statement(const statement& x)
-{
+: statement_proxy_(x.statement_proxy_)
-  statement_proxy_->bind(pos, val, size);
+, bindings_(x.statement_proxy_->create_binder())
+, logger_(x.logger_) {
+}
+statement& statement::operator=(const statement& x) {
+  if (&x == this) {
+    return *this;
+  }
+  statement_proxy_ = x.statement_proxy_;
+  bindings_ = x.statement_proxy_->create_binder();
+  logger_ = x.logger_;
+  return *this;
+}
+
+statement &statement::bind(const size_t pos, const char *value) {
+  statement_proxy_->bind(pos, value, strlen(value), *bindings_);
+  return *this;
+}
+
+statement &statement::bind(const size_t pos, std::string &val, const size_t size) {
+  statement_proxy_->bind(pos, val, size, *bindings_);
   return *this;
 }
 
 utils::result<size_t, utils::error> statement::execute() const {
 //  logger_.info(statement_->query_.sql);
-  return statement_proxy_->execute();
+  return statement_proxy_->execute(*bindings_);
 }
 
 //bool is_unknown(const std::vector<object::column_definition> &columns) {
@@ -39,7 +66,7 @@ utils::result<query_result<record>, utils::error> statement::fetch() const {
 //  }
 
 
-  auto result = statement_proxy_->fetch();
+  auto result = statement_proxy_->fetch(*bindings_);
   if (!result.is_ok()) {
     return utils::failure(result.err());
   }
@@ -49,7 +76,7 @@ utils::result<query_result<record>, utils::error> statement::fetch() const {
 
 utils::result<std::optional<record>, utils::error> statement::fetch_one() const {
     //  logger_.info(statement_->query_.sql);
-    auto result = statement_proxy_->fetch();
+    auto result = statement_proxy_->fetch(*bindings_);
     if (!result.is_ok()) {
         return utils::failure(result.err());
     }

source/orm/sql/statement_cache.cpp

@@ -10,11 +10,11 @@ public:
   explicit statement_cache_proxy(std::unique_ptr<statement_impl>&& stmt)
   : statement_proxy(std::move(stmt)) {}
 
-  utils::result<size_t, utils::error> execute() override {
+  utils::result<size_t, utils::error> execute(interface::parameter_binder& bindings) override {
-    return statement_->execute();
+    return statement_->execute(bindings);
   }
-  utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch() override {
+  utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch(interface::parameter_binder& bindings) override {
-    return statement_->fetch();
+    return statement_->fetch(bindings);
   }
 };
 
@@ -43,8 +43,8 @@ utils::result<statement, utils::error> statement_cache::acquire(const query_cont
 
   // If cache max size reached ensure space
   if (cache_map_.size() >= max_size_) {
-    const size_t& lru_key = usage_list_.back();
+    const auto& key_to_remove = usage_list_.back();
-    cache_map_.erase(lru_key);
+    cache_map_.erase(key_to_remove);
     usage_list_.pop_back();
   }
 

test/orm/backend/test_connection.cpp

@@ -1,4 +1,5 @@
 #include "test_connection.hpp"
+#include "test_statement.hpp"
 #include "test_result_reader.hpp"
 
 #include "matador/sql/query_context.hpp"
@@ -17,25 +18,21 @@ namespace matador::test::orm {
 test_connection::test_connection(const sql::connection_info &info)
 : connection_impl(info) {}
 
-utils::result<void, utils::error> test_connection::open()
+utils::result<void, utils::error> test_connection::open() {
-{
   is_open_ = true;
   return utils::ok<void>();
 }
 
-utils::result<void, utils::error> test_connection::close()
+utils::result<void, utils::error> test_connection::close() {
-{
   is_open_ = false;
   return utils::ok<void>();
 }
 
-utils::result<bool, utils::error> test_connection::is_open() const
+utils::result<bool, utils::error> test_connection::is_open() const {
-{
   return utils::ok(is_open_);
 }
 
-utils::result<bool, utils::error> test_connection::is_valid() const
+utils::result<bool, utils::error> test_connection::is_valid() const {
-{
   return is_open();
 }
 
@@ -47,33 +44,28 @@ utils::result<utils::version, utils::error> test_connection::server_version() co
   return utils::ok(utils::version{3, 2, 1});
 }
 
-utils::result<size_t, utils::error> test_connection::execute(const std::string &/*stmt*/)
+utils::result<size_t, utils::error> test_connection::execute(const std::string &/*stmt*/) {
-{
   return utils::ok(static_cast<size_t>(4));
 }
 
-utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> test_connection::fetch(const sql::query_context &context)
+utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> test_connection::fetch(const sql::query_context &context) {
-{
   return utils::ok(std::make_unique<sql::query_result_impl>(std::make_unique<test_result_reader>(), context.prototype, context.prototype.size()));
 }
 
-utils::result<std::unique_ptr<sql::statement_impl>, utils::error> test_connection::prepare(const sql::query_context &/*context*/)
+utils::result<std::unique_ptr<sql::statement_impl>, utils::error> test_connection::prepare(const sql::query_context &context) {
-{
+  std::unique_ptr<sql::statement_impl> s(std::make_unique<test_statement>(context));
-  return utils::ok(std::unique_ptr<sql::statement_impl>{});
+  return utils::ok(std::move(s));
 }
 
-utils::result<std::vector<object::attribute_definition>, utils::error> test_connection::describe(const std::string &/*table*/)
+utils::result<std::vector<object::attribute_definition>, utils::error> test_connection::describe(const std::string &/*table*/) {
-{
   return utils::ok(std::vector<object::attribute_definition>{});
 }
 
-utils::result<bool, utils::error> test_connection::exists(const std::string &/*schema_name*/, const std::string &/*table_name*/)
+utils::result<bool, utils::error> test_connection::exists(const std::string &/*schema_name*/, const std::string &/*table_name*/) {
-{
   return utils::ok(false);
 }
 
-std::string test_connection::to_escaped_string(const utils::blob& value) const
+std::string test_connection::to_escaped_string(const utils::blob& value) const {
-{
   return utils::to_string(value);
 }
 

test/orm/backend/test_statement.cpp

@@ -1,22 +1,22 @@
 #include "test_statement.hpp"
 #include "test_result_reader.hpp"
+#include "test_parameter_binder.hpp"
 
 namespace matador::test::orm {
 test_statement::test_statement(const sql::query_context &query)
 : statement_impl(query) {}
 
-utils::result<size_t, utils::error> test_statement::execute() {
+utils::result<size_t, utils::error> test_statement::execute(const sql::interface::parameter_binder &/*bindings*/) {
   return utils::ok(static_cast<size_t>(8));
 }
 
-utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> test_statement::fetch() {
+utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> test_statement::fetch(const sql::interface::parameter_binder &/*bindings*/) {
   return utils::ok(std::make_unique<sql::query_result_impl>(std::make_unique<test_result_reader>(), query_.prototype, query_.prototype.size()));
 }
 
 void test_statement::reset() {}
-
+std::unique_ptr<utils::attribute_writer> test_statement::create_binder() const {
-utils::attribute_writer &test_statement::binder() {
+  return std::make_unique<test_parameter_binder>();
-  return binder_;
 }
 
 } // namespace matador::test::orm

test/orm/backend/test_statement.hpp

@@ -1,8 +1,6 @@
 #ifndef TEST_STATEMENT_HPP
 #define TEST_STATEMENT_HPP
 
-#include "test_parameter_binder.hpp"
-
 #include "matador/sql/interface/statement_impl.hpp"
 
 namespace matador::test::orm {
@@ -10,15 +8,12 @@ namespace matador::test::orm {
 class test_statement final : public sql::statement_impl {
 public:
   explicit test_statement(const sql::query_context &query);
-  utils::result<size_t, utils::error> execute() override;
+  utils::result<size_t, utils::error> execute(const sql::interface::parameter_binder &bindings) override;
-  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch() override;
+  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch(const sql::interface::parameter_binder &bindings) override;
   void reset() override;
 
 protected:
-  utils::attribute_writer &binder() override;
+  [[nodiscard]] std::unique_ptr<utils::attribute_writer> create_binder() const override;
-
-private:
-  test_parameter_binder binder_;
 };
 
 }

test/orm/sql/StatementCacheTest.cpp

@@ -17,12 +17,12 @@ TEST_CASE("Test statement cache", "[statement][cache]") {
   backend_provider::instance().register_backend("noop", std::make_unique<orm::test_backend_service>());
 
   connection_pool pool("noop://noop.db", 4);
-  statement_cache cache(pool, 4);
+  statement_cache cache(pool, 2);
 
   query_context ctx;
   ctx.sql = "SELECT * FROM person";
 
-  REQUIRE(cache.capacity() == 4);
+  REQUIRE(cache.capacity() == 2);
   REQUIRE(cache.empty());
 
   auto result = cache.acquire(ctx);
@@ -30,7 +30,25 @@ TEST_CASE("Test statement cache", "[statement][cache]") {
 
   REQUIRE(cache.size() == 1);
   REQUIRE(!cache.empty());
-  REQUIRE(cache.capacity() == 4);
+  REQUIRE(cache.capacity() == 2);
 
   const auto stmt = result.value();
+
+  ctx.sql = "SELECT title FROM book";
+
+  result = cache.acquire(ctx);
+  REQUIRE(result);
+
+  REQUIRE(cache.size() == 2);
+  REQUIRE(!cache.empty());
+  REQUIRE(cache.capacity() == 2);
+
+  ctx.sql = "SELECT name FROM author";
+
+  result = cache.acquire(ctx);
+  REQUIRE(result);
+
+  REQUIRE(cache.size() == 2);
+  REQUIRE(!cache.empty());
+  REQUIRE(cache.capacity() == 2);
 }