// SqlQuery.h 

#ifndef dset__SqlQuery_H
#define dset__SqlQuery_H

// Chitra Kannan
// April 2004
// Fixed by David Adams
// November 2004
//
// Class to build a Sql Query. It is intended to carry the constraint,
// i.e. the where clause.

#include <string>
#include <iosfwd>

namespace dset {

class SqlQuery {

public:  // tyepdefs

  typedef std::string Query;
  typedef std::string constraint;

private: //Data Members

  std::string m_query;
  bool m_validity;

public:  // methods

  // Default constructor.
  SqlQuery(std::string str ="");

  // Also allow construction from a character string.
  SqlQuery(const char* cstr);

  // Destructor.
  virtual ~SqlQuery();

  // Reset the sql query.
  SqlQuery& reset();
 
  // Is the sql query valid
  bool is_valid() const;

  // Set a sql query.
  SqlQuery& set(Query sql);

  // Add AND constraint to sql query.
  SqlQuery& andconstraint(Query constraint);

  // Add OR constraint to sql query.
  SqlQuery& orconstraint(Query constraint);
  
  // Get current sql query.
  std::string to_string() const;

};

}  // end dataset namespace

// Output stream.
std::ostream& operator<< (std::ostream& lhs, const dset::SqlQuery& rhs);

#endif