/sqlite3cc

/*

 * query.h

 *

 * Copyright (C) 2009 Tim Marston <tim@ed.am>

 *

 * This file is part of sqlite3cc (hereafter referred to as "this program").

 * See http://ed.am/dev/sqlite3cc for more information.

 *

 * This program is free software: you can redistribute it and/or modify it under

 * the terms of the GNU Lesser General Public License as published by the Free

 * Software Foundation, either version 3 of the License, or (at your option) any

 * later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

 * details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef SQLITE3CC_QUERY_H_

#define SQLITE3CC_QUERY_H_

#include <boost/iterator/iterator_facade.hpp>

#include <sqlite3cc/basic_statement.h>

#include <sqlite3cc/row.h>

#include <string>

namespace sqlite

{

class query

	:

	public detail::basic_statement

{

//______________________________________________________________________________

//                                                                 instantiation

public:

	/**

	 * Constructor that provides a connection upon which to act and the SQL

	 * query to execute.

	 *

	 * @param connection a reference to a connection

	 * @param sql an SQL statement in UTF-8

	 */

	explicit query(

		connection &connection,

		const std::string &sql );

	/**

	 * Constructor that provides a connection upon which to act.

	 *

	 * @param connection a reference to a connection

	 */

	explicit query(

		connection &connection );

//______________________________________________________________________________

//                                                              public interface

public:

	/**

	 * Prepare an SQL statement.

	 *

	 * @param sql an SQL statement in UTF-8

	 * @returns an sqlite error code

	 * @see sqlite3_prepare_v2()

	 */

	virtual int prepare(

		const std::string &sql );

	/**

	 * Reset the statement, ready to re-execute it.  This does not clear any of

	 * the values bound to the statement.

	 *

	 * @returns an sqlite error code

	 * @see sqlite3_reset()

	 */

	virtual int reset();

	/**

	 * Perform a step() and return row object that can be used to retrieve the

	 * results.

	 *

	 * @return a row object

	 */

	row step();

	/**

	 * Get the number of columns in the results.

	 *

	 * @see sqlite3_column_count()

	 */

	unsigned int column_count();

	/**

	 * Get the name of a column in the results.

	 *

	 * @param index column index

	 * @see sqlite3_column_name()

	 */

	const std::string column_name(

		unsigned int index );

	/**

	 * Gets the number of results.  Be aware that this merely step()s over the

	 * results and counts them, which is something you could do yourself.  This

	 * method is intended to be used for convenience, where you only need know

	 * the number of results and not what they are.  You could also execute some

	 * SQL like this: "SELECT COUNT(*) ...", but this only causes SQLite to

	 * internally do the same counting as this method does.  Also note that this

	 * method reset()s the query.

	 *

	 * @returns the number of results

	 */

	unsigned long long num_results();

	/**

	 * Query iterator which can be used to obtain rows.

	 */

	class iterator

		:

		public boost::iterator_facade< iterator, row,

			boost::single_pass_traversal_tag, row >

	{

	public:

		explicit iterator( query &query, bool step );

	private:

		friend class boost::iterator_core_access;

		row dereference() const;

		void increment();

		bool equal( iterator const &other ) const;

		/** the current row */

		row _row;

		/** the query */

		query &_query;

	};

	/**

	 * Get an iterator to the initial row.  Note that creating an iterator

	 * causes step() to be called, so it should only be called to begin

	 * iterating over the rows and not for comparison.

	 *

	 * @return a query iterator

	 */

	iterator begin();

	/**

	 * Get an iterator to after the last row (i.e., an invalid row).

	 *

	 * @return an invalid query iterator

	 */

	iterator end();

//______________________________________________________________________________

//                                                                implementation

private:

	/** next row number */

	unsigned long long _next_row_number;

};

} // namespace sqlite

#endif /* SQLITE3CC_QUERY_H_ */