Add convenience statement methods in Attachment class

src/fb-cpp/Attachment.cpp

@@ -25,6 +25,9 @@
 #include "Attachment.h"
 #include "Client.h"
 #include "Exception.h"
+#include "RowSet.h"
+#include "Statement.h"
+#include "Transaction.h"
 
 using namespace fbcpp;
 using namespace fbcpp::impl;
@@ -93,3 +96,39 @@ void Attachment::dropDatabase()
 {
 	disconnectOrDrop(true);
 }
+
+bool Attachment::execute(Transaction& transaction, std::string_view sql, const StatementOptions& options)
+{
+	Statement statement{*this, transaction, sql, options};
+	return statement.execute(transaction);
+}
+
+RowSet Attachment::queryRowSet(
+	Transaction& transaction, std::string_view sql, unsigned maxRows, const StatementOptions& options)
+{
+	Statement statement{*this, transaction, sql, options};
+	return queryPreparedRowSet(statement, transaction, maxRows);
+}
+
+RowSet Attachment::queryPreparedRowSet(Statement& statement, Transaction& transaction, unsigned maxRows)
+{
+	switch (statement.getType())
+	{
+		case StatementType::SELECT:
+		case StatementType::SELECT_FOR_UPDATE:
+			break;
+
+		case StatementType::EXEC_PROCEDURE:
+			if (!statement.getOutputDescriptors().empty())
+				break;
+
+			throw FbCppException("Cannot use procedure without output columns with Attachment::queryRowSet");
+
+		default:
+			throw FbCppException("Cannot use non-query SQL with Attachment::queryRowSet");
+	}
+
+	const auto hasRow = statement.execute(transaction);
+	const auto effectiveMaxRows = statement.getType() == StatementType::EXEC_PROCEDURE ? 1u : maxRows;
+	return RowSet{statement, hasRow ? effectiveMaxRows : 0u, hasRow};
+}

src/fb-cpp/Attachment.h

@@ -26,13 +26,16 @@
 #define FBCPP_ATTACHMENT_H
 
 #include "fb-api.h"
+#include "RowSet.h"
 #include "SmartPtrs.h"
+#include "StatementOptions.h"
+#include <cstddef>
 #include <cstdint>
 #include <memory>
 #include <optional>
 #include <string>
+#include <string_view>
 #include <vector>
-#include <cstddef>
 
 
 ///
@@ -41,6 +44,8 @@
 namespace fbcpp
 {
 	class Client;
+	class Statement;
+	class Transaction;
 
 	///
 	/// Represents options used when creating an Attachment object.
@@ -301,14 +306,204 @@ namespace fbcpp
 		///
 		void dropDatabase();
 
+		///
+		/// Prepares and executes an SQL statement using the supplied transaction.
+		///
+		bool execute(Transaction& transaction, std::string_view sql, const StatementOptions& options = {});
+
+		///
+		/// Prepares, binds parameters, and executes an SQL statement using the supplied transaction.
+		///
+		template <typename Params>
+		bool execute(Transaction& transaction, std::string_view sql, const Params& params);
+
+		///
+		/// Prepares, binds parameters, and executes an SQL statement using the supplied transaction and statement
+		/// options.
+		///
+		template <typename Params>
+		bool execute(
+			Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params);
+
+		///
+		/// Prepares and executes a query using the supplied transaction and returns up to maxRows rows.
+		///
+		RowSet queryRowSet(
+			Transaction& transaction, std::string_view sql, unsigned maxRows, const StatementOptions& options = {});
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and returns up to maxRows
+		/// rows.
+		///
+		template <typename Params>
+		RowSet queryRowSet(Transaction& transaction, std::string_view sql, unsigned maxRows, const Params& params);
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and statement options and
+		/// returns up to maxRows rows.
+		///
+		template <typename Params>
+		RowSet queryRowSet(Transaction& transaction, std::string_view sql, unsigned maxRows,
+			const StatementOptions& options, const Params& params);
+
+		///
+		/// Prepares and executes a query using the supplied transaction and returns the first column of the first row.
+		///
+		template <typename T>
+		std::optional<T> queryScalar(
+			Transaction& transaction, std::string_view sql, const StatementOptions& options = {});
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and returns the first column
+		/// of the first row.
+		///
+		template <typename T, typename Params>
+		std::optional<T> queryScalar(Transaction& transaction, std::string_view sql, const Params& params);
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and statement options and
+		/// returns the first column of the first row.
+		///
+		template <typename T, typename Params>
+		std::optional<T> queryScalar(
+			Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params);
+
+		///
+		/// Prepares and executes a query using the supplied transaction and returns the first row mapped as T.
+		///
+		template <typename T>
+		std::optional<T> queryFirstRowAs(
+			Transaction& transaction, std::string_view sql, const StatementOptions& options = {});
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and returns the first row
+		/// mapped as T.
+		///
+		template <typename T, typename Params>
+		std::optional<T> queryFirstRowAs(Transaction& transaction, std::string_view sql, const Params& params);
+
+		///
+		/// Prepares, binds parameters, and executes a query using the supplied transaction and statement options and
+		/// returns the first row mapped as T.
+		///
+		template <typename T, typename Params>
+		std::optional<T> queryFirstRowAs(
+			Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params);
+
 	private:
 		void disconnectOrDrop(bool drop);
+		RowSet queryPreparedRowSet(Statement& statement, Transaction& transaction, unsigned maxRows);
 
 	private:
 		Client* client;
 		FbRef<fb::IAttachment> handle;
 	};
+
+	template <typename T>
+	std::optional<T> Attachment::queryScalar(
+		Transaction& transaction, std::string_view sql, const StatementOptions& options)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, options);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).get<std::optional<T>>(0);
+	}
+
+	template <typename T>
+	std::optional<T> Attachment::queryFirstRowAs(
+		Transaction& transaction, std::string_view sql, const StatementOptions& options)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, options);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).get<T>();
+	}
 }  // namespace fbcpp
 
+#include "Statement.h"
+
+namespace fbcpp
+{
+	template <typename Params>
+	bool Attachment::execute(Transaction& transaction, std::string_view sql, const Params& params)
+	{
+		return execute(transaction, sql, StatementOptions{}, params);
+	}
+
+	template <typename Params>
+	bool Attachment::execute(
+		Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params)
+	{
+		Statement statement{*this, transaction, sql, options};
+		statement.set(params);
+		return statement.execute(transaction);
+	}
+
+	template <typename Params>
+	RowSet Attachment::queryRowSet(
+		Transaction& transaction, std::string_view sql, unsigned maxRows, const Params& params)
+	{
+		return queryRowSet(transaction, sql, maxRows, StatementOptions{}, params);
+	}
+
+	template <typename Params>
+	RowSet Attachment::queryRowSet(Transaction& transaction, std::string_view sql, unsigned maxRows,
+		const StatementOptions& options, const Params& params)
+	{
+		Statement statement{*this, transaction, sql, options};
+		statement.set(params);
+		return queryPreparedRowSet(statement, transaction, maxRows);
+	}
+
+	template <typename T, typename Params>
+	std::optional<T> Attachment::queryScalar(Transaction& transaction, std::string_view sql, const Params& params)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, params);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).template get<std::optional<T>>(0);
+	}
+
+	template <typename T, typename Params>
+	std::optional<T> Attachment::queryScalar(
+		Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, options, params);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).template get<std::optional<T>>(0);
+	}
+
+	template <typename T, typename Params>
+	std::optional<T> Attachment::queryFirstRowAs(Transaction& transaction, std::string_view sql, const Params& params)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, params);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).template get<T>();
+	}
+
+	template <typename T, typename Params>
+	std::optional<T> Attachment::queryFirstRowAs(
+		Transaction& transaction, std::string_view sql, const StatementOptions& options, const Params& params)
+	{
+		auto rowSet = queryRowSet(transaction, sql, 1u, options, params);
+
+		if (rowSet.getCount() == 0u)
+			return std::nullopt;
+
+		return rowSet.getRow(0).template get<T>();
+	}
+}  // namespace fbcpp
 
 #endif  // FBCPP_ATTACHMENT_H

src/fb-cpp/RowSet.cpp

@@ -23,21 +23,28 @@
  */
 
 #include "RowSet.h"
+#include "Attachment.h"
 #include "Client.h"
 #include "Statement.h"
+#include <algorithm>
 
 using namespace fbcpp;
 using namespace fbcpp::impl;
 
 
 RowSet::RowSet(Statement& statement, unsigned maxRows)
+	: RowSet{statement, maxRows, false}
+{
+}
+
+RowSet::RowSet(Statement& statement, unsigned maxRows, bool includeCurrentRow)
 	: client{&statement.getAttachment().getClient()},
 	  statusWrapper{statement.getAttachment().getClient()},
 	  numericConverter{statement.getAttachment().getClient()},
 	  calendarConverter{statement.getAttachment().getClient()}
 {
 	assert(statement.isValid());
-	assert(statement.getResultSetHandle());
+	assert(includeCurrentRow || statement.getResultSetHandle());
 
 	descriptors = statement.getOutputDescriptors();
 
@@ -49,7 +56,22 @@ RowSet::RowSet(Statement& statement, unsigned maxRows)
 	auto resultSet = statement.getResultSetHandle();
 	auto* dest = buffer.data();
 
-	for (unsigned i = 0; i < maxRows; ++i)
+	if (includeCurrentRow && maxRows > 0u)
+	{
+		auto& currentRow = statement.getOutputMessage();
+		assert(currentRow.size() == messageLength);
+		std::copy(currentRow.begin(), currentRow.end(), dest);
+		dest += messageLength;
+		++count;
+	}
+
+	if (!resultSet)
+	{
+		buffer.resize(static_cast<std::size_t>(dest - buffer.data()));
+		return;
+	}
+
+	for (unsigned i = count; i < maxRows; ++i)
 	{
 		if (resultSet->fetchNext(&statusWrapper, dest) != fb::IStatus::RESULT_OK)
 			break;

src/fb-cpp/RowSet.h

@@ -69,6 +69,14 @@ namespace fbcpp
 		///
 		explicit RowSet(Statement& statement, unsigned maxRows);
 
+		///
+		/// @brief Fetches up to `maxRows` rows from the current result set of `statement`.
+		///
+		/// When `includeCurrentRow` is true, the current output message already fetched by `statement.execute()` is
+		/// copied as the first row before fetching the remaining rows from the result set.
+		///
+		explicit RowSet(Statement& statement, unsigned maxRows, bool includeCurrentRow);
+
 		RowSet(RowSet&& o) noexcept
 			: client{o.client},
 			  count{o.count},