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/*=========================================================================
Program: Visualization Toolkit
Module: $RCSfile: vtkSQLQuery.h,v $
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/*----------------------------------------------------------------------------
Copyright (c) Sandia Corporation
See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.
----------------------------------------------------------------------------*/
// .NAME vtkSQLQuery - executes an sql query and retrieves results
//
// .SECTION Description
// The abstract superclass of SQL query classes. Instances of subclasses
// of vtkSQLQuery are created using the GetQueryInstance() function in
// vtkSQLDatabase. To implement a query connection for a new database
// type, subclass both vtkSQLDatabase and vtkSQLQuery, and implement the
// required functions. For the query class, this involves the following:
//
// Execute() - Execute the query on the database. No results need to be
// retrieved at this point, unless you are performing caching.
//
// GetNumberOfFields() - After Execute() is performed, returns the number
// of fields in the query results.
//
// GetFieldName() - The name of the field at an index.
//
// GetFieldType() - The data type of the field at an index.
//
// NextRow() - Advances the query results by one row, and returns whether
// there are more rows left in the query.
//
// DataValue() - Extract a single data value from the current row.
//
// Begin/Rollback/CommitTransaction() - These methods are optional but
// recommended if the database supports transactions.
//
// .SECTION Thanks
// Thanks to Andrew Wilson from Sandia National Laboratories for his work
// on the database classes.
//
// .SECTION See Also
// vtkSQLDatabase
#ifndef __vtkSQLQuery_h
#define __vtkSQLQuery_h
#include "vtkObject.h"
class vtkSQLDatabase;
class vtkVariant;
class vtkVariantArray;
class VTK_IO_EXPORT vtkSQLQuery : public vtkObject
{
public:
vtkTypeRevisionMacro(vtkSQLQuery, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent);
// Description:
// The query string to be executed.
vtkGetStringMacro(Query);
vtkSetStringMacro(Query);
// Description:
// Execute the query. This must be performed
// before any field name or data access functions
// are used.
virtual bool Execute() = 0;
// Description:
// The number of fields in the query result.
virtual int GetNumberOfFields() = 0;
// Description:
// Return the name of the specified query field.
virtual const char* GetFieldName(int i) = 0;
// Description:
// Return the type of the field, using the constants defined in vtkType.h.
virtual int GetFieldType(int i) = 0;
// Description:
// Return the index of the specified query field.
// Uses GetNumberOfFields() and GetFieldName()
// to match field name.
int GetFieldIndex(char* name);
// Description:
// Advance row, return false if past end.
virtual bool NextRow() = 0;
// Description:
// Return true if the query is active (i.e. execution was successful
// and results are ready to be fetched). Returns false on error or
// inactive query.
bool IsActive() { return this->Active; }
// Description:
// Begin, commit, or roll back a transaction. If the underlying
// database does not support transactions these calls will do
// nothing.
virtual bool BeginTransaction() { return true; }
virtual bool CommitTransaction() { return true; }
virtual bool RollbackTransaction() { return true; }
//BTX
// Description:
// Advance row, return false if past end.
// Also, fill array with row values.
bool NextRow(vtkVariantArray* rowArray);
// Description:
// Return data in current row, field c
virtual vtkVariant DataValue(vtkIdType c) = 0;
//ETX
// Description:
// Returns true if an error is set, otherwise false.
virtual bool HasError() = 0;
// Description:
// Get the last error text from the query
virtual const char* GetLastErrorText() = 0;
// Description:
// Return the database associated with the query.
vtkGetObjectMacro(Database, vtkSQLDatabase);
protected:
vtkSQLQuery();
~vtkSQLQuery();
// Description:
// Set the database associated with the query.
// This is only to be called by the corresponding
// database class on creation of the query in
// GetQueryInstance().
void SetDatabase(vtkSQLDatabase* db);
char* Query;
vtkSQLDatabase* Database;
bool Active;
private:
vtkSQLQuery(const vtkSQLQuery &); // Not implemented.
void operator=(const vtkSQLQuery &); // Not implemented.
};
#endif // __vtkSQLQuery_h
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