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Statement.h

//
// Statement.h
//
// $Id: //poco/1.3/Data/include/Poco/Data/Statement.h#3 $
//
// Library: Data
// Package: DataCore
// Module:  Statement
//
// Definition of the Statement class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Data_Statement_INCLUDED
#define Data_Statement_INCLUDED


#include "Poco/Data/Data.h"
#include "Poco/Data/StatementImpl.h"
#include "Poco/Data/Range.h"
#include "Poco/SharedPtr.h"


namespace Poco {
namespace Data {


class AbstractBinding;
class AbstractExtraction;
class Session;
class Limit;


00059 class Data_API Statement
      /// A Statement is used to execute SQL statements. 
      /// It does not contain code of its own.
      /// Its main purpose is to forward calls to the concrete StatementImpl stored inside.
{
public:
      typedef void (*Manipulator)(Statement&);
      
      Statement(StatementImpl* pImpl);
            /// Creates the Statement.

      explicit Statement(Session& session);
            /// Creates the Statement for the given Session.
            ///
            /// The following:
            ///
            ///     Statement stmt(sess);
            ///     stmt << "SELECT * FROM Table", ...
            ///
            /// is equivalent to:
            /// 
            ///     Statement stmt(sess << "SELECT * FROM Table", ...);
            ///
            /// but in some cases better readable.

      ~Statement();
            /// Destroys the Statement.

      Statement(const Statement& stmt);
            /// Copy constructor

      Statement& operator = (const Statement& stmt);
            /// Assignment operator.

      void swap(Statement& other);
            /// Swaps the statement with another one.

      template <typename T> 
00097       Statement& operator << (const T& t)
            /// Concatenates the send data to a string version of the SQL statement.
      {
            _ptr->add(t);
            return *this;
      }

      Statement& operator , (Manipulator manip);
            /// Handles manipulators, such as now.

      Statement& operator , (AbstractBinding* info);
            /// Registers the Binding at the Statement

      Statement& operator , (AbstractExtraction* extract);
            /// Registers objects used for extracting data at the Statement.

      Statement& operator , (const Limit& extrLimit);
            /// Sets a limit on the maximum number of rows a select is allowed to return.
            ///
            /// Set per default to Limit::LIMIT_UNLIMITED which disables the limit.

      Statement& operator , (const Range& extrRange);
            /// Sets a an etxraction Range on the maximum number of rows a select is allowed to return.
            ///
            /// Set per default to Limit::LIMIT_UNLIMITED which disables the range.

      std::string toString() const;
            /// Creates a string from the accumulated SQL statement

      Poco::UInt32 execute();
            /// Executes the whole statement. Stops when either a limit is hit or the whole statement was executed.
            /// Returns the number of rows extracted from the Database.

      bool done();
            /// Returns if the statement was completely executed or if a previously set limit stopped it
            /// and there is more work to do. When no limit is set, it will always - after calling execute() - return true.

      Statement& reset(Session& session);
            /// Resets the Statement so that it can be filled with a new SQL command.

protected:
      const AbstractExtractionVec& extractions() const;
            /// Returns the extractions vector.

      const MetaColumn& metaColumn(std::size_t pos) const;
            /// Returns the type for the column at specified position.

      const MetaColumn& metaColumn(const std::string& name) const;
            /// Returns the type for the column with specified name.

private:
00148       typedef Poco::SharedPtr<StatementImpl> StatementImplPtr;

      bool _executed;
      StatementImplPtr _ptr;
};


//
// Manipulators
//
void Data_API now(Statement& statement);


//
// inlines
//
inline Statement& Statement::operator , (Manipulator manip)
{
      manip(*this);
      return *this;
}


00171 inline Statement& Statement::operator , (AbstractBinding* info)
{
      _ptr->addBinding(info);
      return *this;
}


00178 inline Statement& Statement::operator , (AbstractExtraction* extract)
{
      _ptr->addExtract(extract);
      return *this;
}


00185 inline Statement& Statement::operator , (const Limit& extrLimit)
{
      _ptr->setExtractionLimit(extrLimit);
      return *this;
}


00192 inline Statement& Statement::operator , (const Range& extrRange)
{
      _ptr->setExtractionLimit(extrRange.lower());
      _ptr->setExtractionLimit(extrRange.upper());
      return *this;
}


00200 inline std::string Statement::toString() const
{
      return _ptr->toString();
}


00206 inline const AbstractExtractionVec& Statement::extractions() const
{
      return _ptr->extractions();
}


00212 inline const MetaColumn& Statement::metaColumn(std::size_t pos) const
{
      return _ptr->metaColumn(static_cast<UInt32>(pos));
}


00218 inline const MetaColumn& Statement::metaColumn(const std::string& name) const
{
      return _ptr->metaColumn(name);
}


} } // namespace Poco::Data


#endif // Data_Statement_INCLUDED

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